Novel serpentine transmembrane antigens expressed in human cancers and uses thereof

ABSTRACT

Described is a novel family of cell surface serpentine transmembrane antigens. Two of the proteins in this family are exclusively or predominantly expressed in the prostate, as well as in prostate cancer, and thus members of this family have been termed “STEAP” (Six Transmembrane Epithelial Antigen of the Prostate). Four particular human STEAP&#39;s are described and characterized herein. The human STEAP&#39;s exhibit a high degree of structural conservation among them but show no significant structural homology to any known human proteins. The prototype member of the STEAP family, STEAP-1, appears to be a type IIIa membrane protein expressed predominantly in prostate cells in normal human tissues. Structurally, STEAP-1 is a 339 amino acid protein characterized by a molecular topology of six transmembrane domains and intracellular N- and C-termini, suggesting that it folds in a “serpentine” manner into three extracellular and two intracellular loops. STEAP- 1  protein expression is maintained at high levels across various stages of prostate cancer. Moreover, STEAP-1 is highly over-expressed in certain other human cancers.

RELATED APPLICATIONS

[0001] The application is a continuation of application Ser. No. 09/455,486, filed Dec. 6, 1999, now U.S. Pat. No. ______, which is a continuation-in-part of application Ser. No. 09/323,873, filed Jun. 1, 1999, now U.S. Pat. No. 6,329,503, which claims the benefit of priority to U.S. provisional application No. 60/087,520, filed Jun. 1, 1998, now abandoned, and U.S. provisional application No. 60/091,183, filed Jun. 30, 1998, now abandoned, all of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

[0002] The invention described herein relates to a family of novel genes and their encoded proteins and tumor antigens, termed STEAP's, and to diagnostic and therapeutic methods and compositions useful in the management of various cancers, particularly including prostate cancer, colon cancer, bladder cancer, ovarian cancer and pancreatic cancer.

BACKGROUND ART

[0003] Cancer is the second leading cause of human death next to coronary disease. Worldwide, millions of people die from cancer every year. In the United States alone, cancer causes the death of well over a half-million people annually, with some 1.4 million new cases diagnosed per year. While deaths from heart disease have been declining significantly, those resulting from cancer generally are on the rise. In the early part of the next century, cancer is predicted to become the leading cause of death.

[0004] Worldwide, several cancers stand out as the leading killers. In particular, carcinomas of the lung, prostate, breast, colon, pancreas, and ovary represent the primary causes of cancer death. These and virtually all other carcinomas share a common lethal feature. With very few exceptions, metastatic disease from a carcinoma is fatal. Moreover, even for those cancer patients who initially survive their primary cancers, common experience has shown that their lives are dramatically altered. Many cancer patients experience strong anxieties driven by the awareness of the potential for recurrence or treatment failure. Many cancer patients experience physical debilitations following treatment, and many experience a recurrence.

[0005] Generally speaking, the fundamental problem in the management of the deadliest cancers is the lack of effective and non-toxic systemic therapies. While molecular medicine promises to redefine the ways in which these cancers are managed, progress in this area has been slow despite intensive worldwide efforts to develop novel molecular diagnostics and therapeutics. Fundamental to these efforts is the search for truly tumor-specific genes and proteins that could be used as diagnostic and prognostic markers and/or therapeutic targets or agents.

[0006] As discussed below, the management of prostate cancer serves as a good example of the limited extent to which molecular biology has translated into real progress in the clinic. With limited exceptions, the situation is similar for the other major carcinomas mentioned above.

[0007] Worldwide, prostate cancer is the fourth most prevalent cancer in men. In North America and Northern Europe, it is by far the most common male cancer and is the second leading cause of cancer death in men. In the United States alone, well over 40,000 men die annually of this disease—second only to lung cancer. Despite the magnitude of these figures, there is still no effective treatment for metastatic prostate cancer. Surgical prostatectomy, radiation therapy, hormone ablation therapy, and chemotherapy continue to be the main treatment modalities. Unfortunately, these treatments are ineffective for many and are often associated with undesirable consequences.

[0008] Most prostate cancers initially occur in the peripheral zone of the prostate gland, away from the urethra. Tumors within this zone may not produce any symptoms and, as a result, most men with early-stage prostate cancer will not present clinical symptoms of the disease until significant progression has occurred. Tumor progression into the transition zone of the prostate may lead to urethral obstruction, thus producing the first symptoms of the disease. However, these clinical symptoms are indistinguishable from the common non-malignant condition of benign prostatic hyperplasia (BPH).

[0009] Early detection and diagnosis of prostate cancer currently relies on digital rectal examinations (DRE), prostate specific antigen (PSA) measurements, transrectal ultrasonography (TRUS), and transrectal needle biopsy (TRNB). At present, serum PSA measurement in combination with DRE represent the leading tool used to detect and diagnose prostate cancer. Both have major limitations which have fueled intensive research into finding better diagnostic markers of this disease.

[0010] Accordingly, the lack of a prostate tumor marker that can accurately detect early-stage, localized tumors remains a significant limitation in the management of prostate cancer. A similar problem is the lack of an effective prognostic marker for determining which cancers are indolent and which ones are or will be aggressive. PSA, for example, cannot accurately discriminate between these alternatives.

[0011] Although the serum PSA assay has been a very useful tool, its specificity and general utility is widely regarded as lacking in several important respects. For example, PSA is not a disease-specific marker, as elevated levels of PSA are detectable in a large percentage of patients with BPH and prostatitis (25-86%)(Gao, X., et al., Prostate (1997) 31:264-281), as well as in other nonmalignant disorders and in some normal men. Elevations in serum PSA of between 4 to 10 ng/ml are observed in BPH, and even higher values are observed in prostatitis, particularly acute prostatitis. BPH is an extremely common condition in men. Further confusing the situation is the fact that serum PSA elevations may be observed without any indication of disease from DRE, and vice versa. In addition, PSA diagnostics have sensitivities of only between 57-79% (Cupp, M. R., et al., Mayo Clin Proc (1993) 68:297-306), and thus miss identifying prostate cancer in a significant population of men with the disease. Moreover, it is now recognized that PSA is not prostate-specific (Gao, et al., supra, for review). Various methods designed to improve the specificity of PSA-based detection have been described, such as measuring PSA density and the ratio of free vs. complexed PSA. However, none of these methodologies have been able to reproducibly distinguish benign from malignant prostate disease.

[0012] Similarly, there is no available marker that can predict the emergence of the typically fatal metastatic stage of prostate cancer. Diagnosis of the metastatic stage is presently achieved by open surgical or laparoscopic pelvic lymphadenectomy, whole body radionuclide scans, skeletal radiography, and/or bone lesion biopsy analysis. Clearly, better imaging and less invasive diagnostic methods would improve diagnostic accuracy, ease the burden such procedures place on patients, and open therapeutic options.

[0013] There are some known markers which are expressed predominantly in prostate, such as prostate specific membrane antigen (PSM), a hydrolase with 85% identity to a rat neuropeptidase (Carter, et al., Proc. Natl. Acad. Sci. USA (1996)93:749; Bzdega, et al., J. Neurochem. (1997) 69:2270). However, the expression of PSM in small intestine and brain (Israeli, et al., Cancer Res. (1994) 54:1807), as well its potential role in neuropeptide catabolism in brain, raises concern of potential neurotoxicity with anti-PSM therapies. Preliminary results using an Indium-111 labeled, anti-PSM monoclonal antibody to image recurrent prostate cancer show some promise (Sodee, et al., Clin Nuc Med (1996) 21:759-766). More recently identified prostate cancer markers include PCTA-1 (Su, et al., Proc. Natl. Acad. Sci. USA (1996) 93:7252) and prostate stem cell antigen (PSCA) (Reiter, et al., Proc. Natl. Acad. Sci. USA (1998) 95:1735). PCTA-1, a novel galectin, is largely secreted into the media of expressing cells and may hold promise as a diagnostic serum marker for prostate cancer (Su, et al., 1996). PSCA, a GPI-linked cell surface molecule, was cloned from LAPC-4 cDNA and is unique in that it is expressed primarily in basal cells of normal prostate tissue and in cancer epithelia (Reiter, et al., 1998). Vaccines for prostate cancer are also being actively explored with a variety of antigens, including PSM and PSA.

DISCLOSURE OF THE INVENTION

[0014] The present invention relates to a novel family of cell surface serpentine transmembrane antigens. Two of the proteins in this family are exclusively or predominantly expressed in the prostate, as well as in prostate cancer, and thus members of this family have been termed “STEAP” (Six Transmembrane Epithelial Antigen of the Prostate). Four particular human STEAP's are described and characterized herein. The human STEAP's exhibit a high degree of structural conservation among them but show no significant structural homology to any known human proteins.

[0015] The prototype member of the STEAP family, STEAP-1, appears to be a type IIIa membrane protein expressed predominantly in prostate cells in normal human tissues. Structurally, STEAP-1 is a 339 amino acid protein characterized by a molecular topology of six transmembrane domains and intracellular N- and C-termini, suggesting that it folds in a “serpentine” manner into three extracellular and two intracellular loops. STEAP-1 protein expression is maintained at high levels across various stages of prostate cancer. Moreover, STEAP-1 is highly over-expressed in certain other human cancers. In particular, cell surface expression of STEAP-1 has been definitively confirmed in a variety of prostate and prostate cancer cells, bladder cancer cells and colon cancer cells. These characteristics indicate that STEAP-1 is a specific cell-surface tumor antigen expressed at high levels in prostate, bladder, colon, and other cancers.

[0016] A second member of the family, STEAP-2, is a 454 amino acid protein with a predicted molecular topology similar to that of STEAP-1. STEAP-2, like STEAP-1, is prostate-specific in normal human tissues and is also expressed in prostate cancer. Alignment of the STEAP-2 and STEAP-1 ORF's shows 54.9% identity over a 237 amino acid residue overlap, and the locations of the six putative transmembrane domains in STEAP-2 coincide with the locations of the transmembrane domains in STEAP-1 (FIG. 11A).

[0017] STEAP-3 and STEAP-4 are also described herein. These are also structurally related, and show unique expression profiles. In particular, STEAP-3 and STEAP-4 appear to show a different tissue restriction patterns. An amino acid sequence alignment of all four STEAP's is shown in FIG. 11A.

[0018] The invention provides polynucleotides corresponding or complementary to all or part of the STEAP genes, mRNA's, and/or coding sequences, preferably in isolated form, including polynucleotides encoding STEAP proteins and fragments thereof, DNA, RNA, DNA/RNA hybrid, and related molecules, polynucleotides or oligonucleotides complementary to the STEAP genes or mRNA sequences or parts thereof, and polynucleotides or oligonucleotides which hybridize to the STEAP genes, mRNA's, or to STEAP-encoding polynucleotides. Also provided are means for isolating cDNA's and the genes encoding STEAP's. Recombinant DNA molecules containing STEAP polynucleotides, cells transformed or transduced with such molecules, and host-vector systems for the expression of STEAP gene products are also provided. The invention further provides STEAP proteins and polypeptide fragments thereof. The invention further provides antibodies that bind to STEAP proteins and polypeptide fragments thereof, including polyclonal and monoclonal antibodies, murine and other mammalian antibodies, chimeric antibodies, humanized and fully human antibodies, and antibodies labeled with a detectable marker, and antibodies conjugated to radionuclides, toxins or other therapeutic compositions. The invention further provides methods for detecting the presence of STEAP polynucleotides and proteins in various biological samples, as well as methods for identifying cells that express a STEAP. The invention further provides various therapeutic compositions and strategies for treating prostate cancer, including particularly, antibody, vaccine and small molecule therapy.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1. STEAP-1 structure. 1A: Nucleotide and deduced amino acid sequences of STEAP-1 (8P1B4) clone 10 cDNA (SEQ ID NOS. 1 and 2, respectively). The start Methionine is indicated in bold at amino acid residue position 1 and six putative transmembrane domains are indicated in bold and are underlined. 1B: Schematic representation of STEAP-1 transmembrane orientation; amino acid residues bordering the predicted extracellular domains are indicated and correspond to the numbering scheme of FIG. 1A. 1C: G/C rich 5′ non-coding sequence of the STEAP-1 gene as determined by overlapping sequences of clone 10 and clone 3 (SEQ ID NO: 3).

[0020]FIG. 2. Predominant expression of STEAP-1 in prostate tissue. First strand cDNA was prepared from 16 normal tissues, the LAPC xenografts (4AD, 4AI and 9AD) and HeLa cells. Normalization was performed by PCR using primers to actin and GAPDH. Semi-quantitative PCR, using primers derived from STEAP-1 (8P1D4) cDNA (FIG. 1A), shows predominant expression of STEAP-1 in normal prostate and the LAPC xenografts. The following primers were used to amplify STEAP-1: 8P1D4.1 5′ ACTTTGTTGATGACCAGGATTGGA 3′ (SEQ ID NO: 14) 8P1D4.2 5′ CAGAACTTCAGCACACACAGGAAC 3′ (SEQ ID NO: 15)

[0021]FIG. 3. Northern blot analyses of STEAP-1 expression in various normal human tissues and prostate cancer xenografts, showing predominant expression of STEAP-1 in prostate tissue. FIG. 3A: Two multiple tissue northern blots (Clontech) were probed with a full length STEAP cDNA clone 10 (FIG. 1A; SEQ ID NO: 1). Size standards in kilobases (kb) are indicated on the side. Each lane contains 2 μg of mRNA that was normalized by using a β-actin probe. FIG. 3B: Multiple tissue RNA dot blot (Clontech, Human Master Blot cat# 7770-1) probed with STEAP-1 cDNA clone 10 (FIG. 1A; SEQ ID NO: 1), showing approximately five-fold greater expression in prostate relative to other tissues with significant detectable expression.

[0022]FIG. 4. Nucleotide sequence of STEAP-1 GTH9 clone (SEQ ID NO: 4) corresponding to the 4 kb message on northern blots (FIG. 3A). The sequence contains an intron of 2399 base pairs relative to the STEAP-1 clone 10 sequence of FIG. 1A; coding regions are nucleotides 96-857 and 3257-3510 (indicated in bold). The start ATG is in bold and underlined, the STOP codon is in bold and underlined, and the intron-exon boundaries are underlined.

[0023]FIG. 5. Expression of STEAP-1 in prostate and multiple cancer cell lines and prostate cancer xenografts. Xenograft and cell line filters were prepared with 10 μg of total RNA per lane. The blots were analyzed using the STEAP-1 clone 10 as probe. All RNA samples were normalized by ethidium bromide staining and subsequent analysis with a β-actin probe. FIG. 5A: Expression in various cancer cell lines and xenografts and prostate. Lanes as follows: (1) PrEC cells, (2) normal prostate tissue, (3) LAPC-4 AD xenograft, (4) LAPC-4 AI xenograft, (5) LAPC-9 AD xenograft, (6) LAPC-9 AI xenograft, (7) LNCaP cells, (8) PC-3 cells, (9) DU145 cells, (10) PANC-1 cells, (11) BxPC-3 cells, (12) HPAC cells, (13) Capan-1 cells, (14) CACO-2 cells, (15) LOVO cells, (16) T84 cells, (17) COLO-205 cells, (18) KCL-22 cells (acute lymphocytic leukemia, ALL), (19) HT1197 cells, (20) SCABER cells, (21) UM-UC-3 cells, (22) TCCSUP cells, (23) J82 cells, (24) 5637 cells, (25) RD-ES cells (Ewing sarcoma, EWS), (26) CAMA-1 cells, (27) DU4475 cells, (28) MCF-7 cells, (29) MDA-MB-435s cells, (30) NTERA-2 cells, (31) NCCIT cells, (32) TERA-1 cells, (33) TERA-2 cells, (34) A431 cells, (35) HeLa cells, (36) OV-1063 cells, (37) PA-1 cells, (38) SW 626 cells, (39) CAOV-3 cells. FIG. 5B: The expression of STEAP-1 in subcutaneously (sc) grown LAPC xenografts compared to the expression in LAPC-4 and LAPC-9 xenografts grown in the tibia (it) of mice.

[0024]FIG. 6. Western blot analysis of STEAP-1 protein expression in tissues and multiple cell lines. Western blots of cell lysates prepared from prostate cancer xenografts and cell lines were probed with a polyclonal anti-STEAP-1 antibody preparation (see Example 3C for details). The samples contain 20 μg of protein and were normalized with anti-Grb-2 probing of the Western blots.

[0025]FIG. 7. Cell surface biotinylation of STEAP-1. FIG. 7A: Cell surface biotinylation of 293T cells transfected with vector alone or with vector containing cDNA encoding 6His-tagged STEAP-1. Cell lysates were immunoprecipitated with specific antibodies, transferred to a membrane and probed with horseradish peroxidase-conjugated streptavidin. Lanes 1-4 and 6 correspond to immunoprecipitates from lysates prepared from STEAP-1 expressing 293T cells. Lanes 5 and 7 are immunoprecipitates from vector transfected cells. The immunoprecipitations were performed using the following antibodies: (1) sheep non-immune, (2) anti-Large T antigen, (3) anti-CD71 (transferrin receptor), (4) anti-His, (5) anti-His, (6) anti-STEAP-1, (7) anti-STEAP-1. FIG. 7B: Prostate cancer (LNCaP, PC-3, DU145), bladder cancer (UM-UC-3, TCCSUP) and colon cancer (LOVO, COLO) cell lines were either biotinylated (+) or not (−) prior to lysis. Western blots of streptavidin-gel purified proteins were probed with anti-STEAP-1 antibodies. Molecular weight markers are indicated in kilo Daltons (kD).

[0026]FIG. 8. Immunohistochemical analysis of STEAP-1 expression using anti-STEAP-1 polyclonal antibody. Tissues were fixed in 10% formalin and embedded in paraffin. Tissue sections were stained using anti-STEAP-1 polyclonal antibodies directed towards the N-terminal peptide. Samples include: (a) LNCaP cells probed in the presence of N-terminal STEAP-1 peptide 1, (b) LNCaP plus non specific peptide 2, (c) normal prostate tissue, (d) grade 3 prostate carcinoma, (e) grade 4 prostate carcinoma, (f) LAPC-9 AD xenograft, (g) normal bladder, (h) normal colon. All images are at 400× magnification.

[0027]FIG. 9. Nucleotide and deduced amino acid sequences of STEAP-2 (98P4B6) clone GTD3 cDNA (SEQ ID NOS: 5 and 6, respectively). The start methionine and Kozak sequence are indicated in bold, and the putative transmembrane domains are underlined in bold. The 5′ UTR exhibits a high GC content of 72%

[0028]FIG. 10A. Nucleotide and deduced amino acid sequences of STEAP-3 (SEQ ID NOS: 7 and 8, respectively). Kozak region is bolded. FIG. 10B. Nucleotide sequences of dbEST database entries corresponding to additional STEAP family members obtained by searching with the protein sequence of STEAP-1 (SEQ ID NOS: 9, 10, 11 and 12).

[0029]FIG. 11. Primary structural comparisons of STEAP family proteins:

[0030]FIG. 11A. Amino acid sequence alignment of STEAP's 1-4 using PIMA program (PIMA 1.4 program at Internet address: <http:\\dot.imgen.bcm.tmc.edu:9331\multi-align\multi-align.html>); transmembrane domains identified by the SOSUI program (available at Internet address <http:\\www.tuat.acjp\˜mitaku\adv_sosui\submit.html>) are in bold. PIMA maximal linkage clustering results shown; identical residues shown in bold.

[0031]FIG. 11B. Amino acid sequence alignment of STEAP-1 (8P1D4 clone 10; SEQ ID NO: 2) and STEAP-2 (98P4B6 clone GTD3; SEQ ID NO: 6) sequences. The alignment was performed using the SIM alignment program of the Baylor College of Medicine Search Launcher Web site. Transmembrane domains are indicated in boldface. The results show a 54.9% identity in a 237 residues overlap (Score: 717.0; Gap frequency: 0.0%).

[0032]FIG. 11C. Amino acid sequence alignment of STEAP-1 and STEAP-3 (98P4B6 clone GTD3; SEQ ID NO: 8) sequences. Identical residues indicated with asterisks. SIM results: 40.9% identity in 264 residues overlap; Score: 625.0; Gap frequency: 0.0%.

[0033]FIG. 11D. Amino acid sequence alignment of STEAP-2 and STEAP-3 (98P4B6 clone GTD3; SEQ ID NO: 8) sequences. Identical residues indicated with asterisks. SIM results: 47.8% identity in 416 residues overlap; Score: 1075.0; Gap frequency: 0.2%.

[0034]FIG. 12. Expression of STEAP-3 mRNA in normal tissues by Northern blot (FIG. 12A) and RT-PCR (FIG. 12B). For RT-PCR analysis, first strand cDNA was prepared from 16 normal tissues. Normalization was performed by PCR using primers to actin and GAPDH. Semi-quantitative PCR, using primers to AI139607, shows predominant expression of AI139607 in placenta and prostate after 25 cycles of amplification. The following primers were used to amplify AI139607: AI139607.1 5′ TTAGGACAACTTGATCACCAGCA 3′ (SEQ ID NO: 16) AI139607.2 5′ TGTCCAGTCCAAACTGGGTTATTT 3′ (SEQ ID NO: 17)

[0035]FIG. 13. Predominant expression of STEAP-4/R80991 in liver. First strand cDNA was prepared from 16 normal tissues. Normalization was performed by PCR using primers to actin and GAPDH. Semi-quantitative PCR, using primers to R80991, shows predominant expression of R80991 in liver after 25 cycles of amplification. The following primers were used to amplify R80991: R80991.1 5′ AGGGAGTTCAGCTTCGTTCAGTC 3′ (SEQ ID NO: 18) R80991.2 5′ GGTAGAACTTGTAGCGGCTCTCCT 3′ (SEQ ID NO: 19)

[0036]FIG. 14. Predominant expression of STEAP-2 (98P4B6) in prostate tissue. First strand cDNA was prepared from 8 normal tissues, the LAPC xenografts (4AD, 4AI and 9AD) and HeLa cells. Normalization was performed by PCR using primers to actin and GAPDH. Semi-quantitative PCR, using primers to 98P4B6, shows predominant expression of 98P4B6 in normal prostate and the LAPC xenografts. The following primers were used to amplify STEAP II: 98P4B6.1 5′ GACTGAGCTGGAACTGGAATTTGT 3′ (SEQ ID NO: 20) 98P4B6.2 5′ TTTGAGGAGACTTCATCTCACTGG 3′ (SEQ ID NO: 21)

[0037]FIG. 15. Expression of the prostate-specific STEAP-2/98P4B6 gene in normal tissues and in prostate cancer xenografts determined by Northern blot analysis. Human normal tissue filters (A and B) were obtained from Clontech and contain 2 μg of mRNA per lane. Xenograft filter (C) was prepared with 10 μg of total RNA per lane. The blots were analyzed using the SSH derived 98P4B6 clone as probe. All RNA samples were normalized by ethidium bromide staining.

[0038]FIG. 16. Expression of STEAP-2 in prostate and select cancer cell lines as determined by Northern blot analysis. Xenograft and cell line filters were prepared with 10 μg total RNA per lane. The blots were analyzed using an SSH derived 98P4B6 clone as probe. All RNA samples were normalized by ethidium bromide staining.

[0039]FIG. 17. Chromosomal localization of STEAP family members. The chromosomal localizations of the STEAP genes described herein were determined using the GeneBridge4 radiation hybrid panel (Research Genetics, Huntsville Ala.). The mapping for STEAP-2 and AI139607 was performed using the Stanford G3 radiation hybrid panel (Research Genetics, Huntsville Ala.).

[0040]FIG. 18. Schematic representation of Intron-Exon boundaries within the ORF of human STEAP-1 gene. A total of 3 introns (i) and 4 exons (e) were identified.

[0041]FIG. 19. Zooblot southern analysis of STEAP-1 gene in various species. Genomic DNA was prepared from several different organisms including human, monkey, dog, mouse, chicken and Drosophila. Ten micrograms of each DNA sample was digested with EcoRI, blotted onto nitrocellulose and probed with a STEAP-1 probe. Size standards are indicated on the side in kilobases (kb).

[0042]FIG. 20. Southern blot analysis of mouse BAC with a STEAP-1 probe. DNA was prepared from human cells to isolate genomic DNA and from a mouse BAC clone (12P11) that contains the mouse STEAP gene. Each DNA sample was digested with EcoRI, blotted onto nitrocellulose and probed. Eight micrograms of genomic DNA was compared to 250 ng of mouse BAC DNA.

MODES OF CARRYING OUT THE INVENTION

[0043] Unless otherwise defined, all terms of art, notations and other scientific terminology used herein are intended to have the meanings commonly understood by those of skill in the art to which this invention pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art. The techniques and procedures described or referenced herein are generally well understood and commonly employed using conventional methodology by those skilled in the art, such as, for example, the widely utilized molecular cloning methodologies described in Sambrook, et al., Molecular Cloning: A Laboratory Manual, 2nd. edition (1989) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. As appropriate, procedures involving the use of commercially available kits and reagents are generally carried out in accordance with manufacturer defined protocols and/or parameters unless otherwise noted.

[0044] As used herein, the terms “advanced prostate cancer”, “locally advanced prostate cancer”, “advanced disease” and “locally advanced disease” mean prostate cancers which have extended through the prostate capsule, and are meant to include stage C disease under the American Urological Association (AUA) system, stage C1-C2 disease under the Whitmore-Jewett system, and stage T3-T4 and N+ disease under the TNM (tumor, node, metastasis) system. In general, surgery is not recommended for patients with locally advanced disease, and these patients have substantially less favorable outcomes compared to patients having clinically localized (organ-confined) prostate cancer. Locally advanced disease is clinically identified by palpable evidence of induration beyond the lateral border of the prostate, or asymmetry or induration above the prostate base. Locally advanced prostate cancer is presently diagnosed pathologically following radical prostatectomy if the tumor invades or penetrates the prostatic capsule, extends into the surgical margin, or invades the seminal vesicles.

[0045] As used herein, the terms “metastatic prostate cancer” and “metastatic disease” mean prostate cancers which have spread to regional lymph nodes or to distant sites, and are meant to include stage D disease under the AUA system and stage TxNxM+under the TNM system. As is the case with locally advanced prostate cancer, surgery is generally not indicated for patients with metastatic disease, and hormonal (androgen ablation) therapy is the preferred treatment modality. Patients with metastatic prostate cancer eventually develop an androgen-refractory state within 12 to 18 months of treatment initiation, and approximately half of these patients die within 6 months thereafter. The most common site for prostate cancer metastasis is bone. Prostate cancer bone metastases are, on balance, characteristically osteoblastic rather than osteolytic (i.e., resulting in net bone formation). Bone metastases are found most frequently in the spine, followed by the femur, pelvis, rib cage, skull and humerus. Other common sites for metastasis include lymph nodes, lung, liver and brain. Metastatic prostate cancer is typically diagnosed by open or laparoscopic pelvic lymphadenectomy, whole body radionuclide scans, skeletal radiography, and/or bone lesion biopsy.

[0046] As used herein, the term “polynucleotide” means a polymeric form of nucleotides of at least 10 bases or base pairs in length, either ribonucleotides or deoxynucleotides or a modified form of either type of nucleotide, and is meant to include single and double stranded forms of DNA.

[0047] As used herein, the term “polypeptide” means a polymer of at least 8 amino acids. Throughout the specification, standard three letter or single letter designations for amino acids are used.

[0048] As used herein, the terms “hybridize”, “hybridizing”, “hybridizes” and the like, used in the context of polynucleotides, are meant to refer to conventional hybridization conditions, preferably such as hybridization in 50% formamide/6×SSC/0.1% SDS/100 μg/ml ssDNA, in which temperatures for hybridization are above 37° C. and temperatures for washing in 0.1×SSC/0.1% SDS are above 55° C., and most preferably to stringent hybridization conditions.

[0049] In the context of amino acid sequence comparisons, the term “identity” is used to express the percentage of amino acid residues at the same relative position which are the same. Also in this context, the term “homology” is used to express the percentage of amino acid residues at the same relative positions which are either identical or are similar, using the conserved amino acid criteria of BLAST analysis, as is generally understood in the art. Further details regarding amino acid substitutions, which are considered conservative under such criteria, are provided below.

[0050] Additional definitions are provided throughout the subsections which follow.

[0051] Molecular and Biochemical Features of the STEAP's

[0052] The invention relates to a novel family of proteins, termed STEAP's. Four STEAP's are specifically described herein by way of structural, molecular and biochemical features. As is further described in the Examples which follow, the STEAP's have been characterized in a variety of ways. For example, analyses of nucleotide coding and amino acid sequences were conducted in order to identify conserved structural elements within the STEAP family. Extensive RT-PCR and Northern blot analyses of STEAP mRNA expression were conducted in order to establish the range of normal and cancerous tissues expressing the various STEAP messages. Western blot, immunohistochemical and flow cytometric analyses of STEAP protein expression were conducted to determine protein expression profiles, cell surface localization and gross molecular topology of STEAP.

[0053] The prototype member of the STEAP family, STEAP-1, is a six-transmembrane cell surface protein of 339 amino acids with no identifiable homology to any known human protein. The cDNA nucleotide and deduced amino acid sequences of human STEAP-1 are shown in FIG. 1A. A gross topological schematic of the STEAP-1 protein integrated within the cell membrane is shown in FIG. 1B. STEAP-1 expression is predominantly prostate-specific in normal tissues. Specifically, extensive analysis of STEAP-1 mRNA and protein expression in normal human tissues shows that STEAP-1 protein is predominantly expressed in prostate and, to a far smaller degree, in bladder. STEAP-1 mRNA is also relatively prostate specific, with only very low level expression detected in a few other normal tissues. In cancer, STEAP-1 mRNA and protein is consistently expressed at high levels in prostate cancer (including androgen-dependent and androgen-independent tumors) and during all stages of the disease. STEAP-1 is also expressed in other cancers. Specifically, STEAP-1 mRNA is expressed at very high levels in bladder, colon, pancreatic, and ovarian cancer (as well as other cancers). In addition, cell surface expression of STEAP-1 protein has been established in prostate, bladder and colon cancers. Therefore, STEAP-1 has all of the hallmark characteristics of an excellent therapeutic target for the treatment of certain cancers, including particularly prostate, colon and bladder carcinomas.

[0054] A second member of the family, STEAP-2, is a 454 amino acid protein encoded by a distinct gene and having a predicted molecular topology similar to that of STEAP-1. The cDNA nucleotide and deduced amino acid sequences of STEAP-2 are shown in FIG. 9. Amino acid alignment of the STEAP-1 and STEAP-2 sequences show a high degree of structural conservation (54.9% identity over a 237 amino acid residue overlap, and the locations of the six putative transmembrane domains in STEAP-1 and STEAP-2 coincide (FIGS. 11A and 11B). Structural homology between these STEAP-1 and STEAP-2 is highest in the regions spanned by the first putative extracellular loop to the fifth transmembrane domain. However, some significant structural differences between STEAP-1 and STEAP-2 are apparent. For example, STEAP-2 exhibits a 205 a.a. long intracellular N-terminus (compared to 69 a.a. in STEAP-1) and a short 4 a.a. intracellular C-terminus (compared to 26 a.a. in STEAP-1). In addition, both the STEAP-1 and STEAP-2 genes are located on chromosome 7, but on different arms. These differences could imply significant differences in function and/or interaction with intracellular signaling pathways.

[0055] STEAP-2 is expressed only in normal prostate among human tissues tested (FIGS. 14 and 15) and is also expressed in prostate cancer (FIG. 15), and thus shows some similarity in expression profile to STEAP-1. However, STEAP-2 exhibits a different mRNA expression profile relative to STEAP-1 in prostate cancer samples (compare FIGS. 3 and 15) and in other non-prostate cancers tested (compare FIGS. 5 and 16). These differences in the expression profiles of STEAP-1 and STEAP-2 suggest that they are differentially regulated.

[0056] STEAP-3 and STEAP-4 appear to be closely related to both STEAP-1 and STEAP-2 on a structural level, and both appear to be transmembrane proteins as well. STEAP-3 is more related to STEAP-2 (47.8% identity) than to STEAP-1 (40.9% identity). STEAP-3 and STEAP-4 show unique expression profiles. STEAP-3, for example, appears to have an expression pattern which is predominantly restricted to placenta and, to a smaller degree, expression is seen in prostate but not in other normal tissues tested. STEAP-4 seems to be expressed predominantly in liver by RT-PCR analysis. Neither STEAP-3 nor STEAP-4 appear to be expressed in prostate cancer xenografts which exhibit high level STEAP-1 and STEAP-2 expression.

[0057] Three of the four STEAP's described herein map to human chromosome 7 (STEAP-1, -2 and -3). Interestingly, STEAP-1 maps within 7p22 (7p22.3), a large region of allelic gain reported for both primary and recurrent prostate cancers (Visakorpi, T., et al., Cancer Res. (1995) 55:342-347, Nupponen, N. N., et al., American J. Pathol. (1998) 153:141-148), suggesting that up-regulation of STEAP-1 in cancer might include genomic mechanisms. In addition, both STEAP-2 and STEAP-3 locate to chromosome 7q21, suggesting that these two genes arose by gene duplication.

[0058] The function of the STEAP's are not known. Other cell surface molecules that contain six transmembrane domains include ion channels (Dolly, J. O., et al., J. Bioenerg. Biomembr. (1996) 28:231-253) and water channels or aquaporins (Reizer, J., et al., Crit. Rev. Biochem. Mol. Biol. (1993) 28:237-257). Structural studies show that both types of molecules assemble into tetrameric complexes to form functional channels (Christie, M. J., Clin. Exp. Pharmacol. Physiol. (1995) 22:944-951, Walz, T., et al., Nature (1997) 387:624-627, Cheng, A., et al., Nature (1997) 387:627-630). Immunohistochemical staining of STEAP-1 in the prostate gland seems to be concentrated at the cell-cell boundaries, with less staining detected at the luminal side. This may suggest a role for STEAP-1 in tight-junctions, gap-junctions or cell communication and adhesion. In order to test these possibilities, Xenopus oocytes (or other cells) expressing STEAP may be analyzed using voltage-clamp and patch-clamp experiments to determine if STEAP functions as an ion-channel. Oocyte cell volume may also be measured to determine if STEAP exhibits water channel properties. If STEAP's function as channel or gap-junction proteins, they may serve as excellent targets for inhibition using, for example, antibodies, small molecules, and polynucleotides capable of inhibiting expression or function. The restricted expression pattern in normal tissue, and the high levels of expression in cancer tissue suggest that interfering with STEAP function may selectively kill cancer cells.

[0059] Since the STEAP gene family is predominantly expressed in epithelial tissue, it seems possible that the STEAP proteins function as ion channels, transport proteins or gap-junction proteins in epithelial cell function. Ion channels have been implicated in proliferation and invasiveness of prostate cancer cells (Lalani, E. N., et al., Cancer Metastasis Rev. (1997) 16:29-66). Both rat and human prostate cancer cells contain sub-population of cells with higher and lower expression levels of sodium channels. Higher levels of sodium channel expression correlate with more aggressive invasiveness in vitro (Smith, P., et al., FEBS Lett. (1998) 423:19-24). Similarly, it has been shown that a specific blockade of sodium channels inhibits the invasiveness of PC-3 cells in vitro (Laniado, M. E., et al., Am. J. Pathol. (1997) 150:1213-1221), while specific inhibition of potassium channels in LNCaP cells inhibited cell proliferation (Skryma, R. N., et al., Prostate (1997) 33:112-122). These reports suggest a role for ion channels in prostate cancer and also demonstrate that small molecules that inhibit ion channel function may interfere with prostate cancer proliferation.

[0060] STEAP Polynucleotides

[0061] One aspect of the invention provides polynucleotides corresponding or complementary to all or part of a STEAP gene, mRNA, and/or coding sequence, preferably in isolated form, including polynucleotides encoding a STEAP protein and fragments thereof, DNA, RNA, DNA/RNA hybrid, and related molecules, polynucleotides or oligonucleotides complementary to a STEAP gene or mRNA sequence or a part thereof, and polynucleotides or oligonucleotides which hybridize to a STEAP gene, mRNA, or to a STEAP-encoding polynucleotide (collectively, “STEAP polynucleotides”). As used herein, STEAP genes and proteins are meant to include the STEAP-1, STEAP-2 and STEAP-3 genes and proteins, and the gene and protein corresponding to GenBank Accession number R80991 (STEAP-4), and the genes and proteins corresponding to other STEAP proteins and structurally similar variants of the foregoing. Such other STEAP proteins and variants will generally have coding sequences which are highly homologous to the STEAP coding sequences provided herein, and preferably will share at least about 50% amino acid identity and at least about 60% amino acid homology (using BLAST criteria), more preferably sharing 70% or greater homology (using BLAST criteria).

[0062] The STEAP family member gene sequences described herein encode STEAP proteins sharing unique highly conserved amino acid sequence domains which distinguish them from other proteins. Proteins which include one or more of these unique highly conserved domains may be related to the STEAP family members or may represent new STEAP proteins. Referring to FIG. 11A, which is an amino acid sequence alignment of the full STEAP-1, STEAP-2, and STEAP-3 protein sequences as well as the partial STEAP-4 sequence, it is clear that the STEAP's are closely related at the structural level. Referring to FIG. 11B, which is an amino acid sequence alignment of the full STEAP-1 and STEAP-2 protein sequences, close structural conservation is apparent, particularly in the predicted transmembrane domains. The STEAP-1 and STEAP-2 sequences share 54.9% identity over a 237 amino acid overlap. Additional amino acid sequence alignments between the STEAP's are shown in FIGS. 11C and 11D. These alignments show that STEAP-1 and STEAP-3 are 40.9% identical over a 264 amino acid region, while STEAP-2 and STEAP-3 are 47.8% identical over a 416 amino acid region.

[0063] A STEAP polynucleotide may comprise a polynucleotide having the nucleotide sequence of human STEAP-1 as shown in FIG. 1A, the nucleotide sequence of human STEAP-2 as shown in FIG. 9, the nucleotide sequence of human STEAP-3 as shown in FIG. 10A, or the nucleotide sequence of STEAP-4 as shown in FIG. 10B, or a sequence complementary thereto, or a polynucleotide fragment of any of the foregoing. Another embodiment comprises a polynucleotide which encodes the human STEAP-1, STEAP-2, STEAP-3 or STEAP-4 protein amino acid sequences, a sequence complementary thereto, or a polynucleotide fragment of any of the foregoing. Another embodiment comprises a polynucleotide which is capable of hybridizing under stringent hybridization conditions to the human STEAP-1 cDNA shown in FIG. 1A, the human STEAP-2 cDNA shown in FIG. 9, the human STEAP-3 cDNA shown in FIG. 10A, or the STEAP-4 as shown in FIG. 10B, or to a polynucleotide fragment thereof.

[0064] Specifically contemplated are genomic DNA, cDNA's, ribozymes, and antisense molecules, as well as nucleic acid molecules based on an alternative backbone or including alternative bases, whether derived from natural sources or synthesized. For example, antisense molecules can be RNA's or other molecules, including peptide nucleic acids (PNA's) or non-nucleic acid molecules such as phosphorothioate derivatives, that specifically bind DNA or RNA in a base pair-dependent manner. The skilled person can readily obtain these classes of nucleic acid molecules using the STEAP polynucleotides and polynucleotide sequences disclosed herein.

[0065] Further specific embodiments of this aspect of the invention include primers and primer pairs, which allow the specific amplification of the polynucleotides of the invention or of any specific parts thereof, and probes that selectively or specifically hybridize to nucleic acid molecules of the invention or to any part thereof. Probes may be labeled with a detectable marker, such as, for example, a radioisotope, fluorescent compound, bioluminescent compound, a chemiluminescent compound, metal chelator or enzyme. Such probes and primers can be used to detect the presence of a STEAP polynucleotide in a sample and as a means for detecting a cell expressing a STEAP protein. Examples of such probes include polynucleotides comprising all or part of the human STEAP-1, STEAP-2 and STEAP-3 cDNA sequences shown in FIGS. 1A, 9 and 10A, respectively. Examples of primer pairs capable of specifically amplifying STEAP mRNA's are also described in the Examples which follow. As will be understood by the skilled person, a great many different primers and probes may be prepared based on the sequences provided in herein and used effectively to amplify and/or detect a STEAP mRNA or an mRNA encoding a particular STEAP family member.

[0066] As used herein, a polynucleotide is said to be “isolated” when it is substantially separated from contaminant polynucleotides which correspond or are complementary to genes other than the STEAP gene from which the polynucleotide is derived or which encode polypeptides other than the corresponding STEAP gene product or fragment thereof. The skilled person can readily employ nucleic acid isolation procedures to obtain an isolated STEAP polynucleotides.

[0067] The STEAP polynucleotides of the invention are useful for a variety of purposes, including but not limited to their use as probes and primers for the amplification and/or detection of the STEAP gene(s), mRNA(s), or fragments thereof; as reagents for the diagnosis and/or prognosis of prostate cancer and other cancers; as coding sequences capable of directing the expression of STEAP polypeptides; as tools for modulating or inhibiting the expression of the STEAP gene(s) and/or translation of the STEAP transcript(s); and as therapeutic agents.

[0068] Methods for Isolating STEAP-Encoding Nucleic Acid Molecules

[0069] The STEAP cDNA sequences described herein enable the isolation of other polynucleotides encoding STEAP gene product(s), as well as the isolation of polynucleotides encoding STEAP gene product homologues, alternatively spliced isoforms, allelic variants, and mutant forms of the STEAP gene product. Various molecular cloning methods that can be employed to isolate full length cDNA's encoding a STEAP gene are well known (See, for example, Sambrook, J., et al., Molecular Cloning: A Laboratory Manual, 2d edition., Cold Spring Harbor Press, New York, 1989; Current Protocols in Molecular Biology, Ausubel, et al., Eds., Wiley and Sons, 1995). For example, lambda phage cloning methodologies may be conveniently employed, using commercially available cloning systems (e.g., Lambda ZAP Express, Stratagene). Phage clones containing STEAP gene cDNA's may be identified by probing with a labeled STEAP cDNA or a fragment thereof. For example, in one embodiment, the STEAP-1 cDNA (FIG. 1A) or a portion thereof can be synthesized and used as a probe to retrieve overlapping and full length cDNA's corresponding to a STEAP gene. Similarly, the STEAP-2 and STEAP-3 cDNA sequences may be employed. A STEAP gene may be isolated by screening genomic DNA libraries, bacterial artificial chromosome libraries (BAC's), yeast artificial chromosome libraries (YAC's), and the like, with STEAP DNA probes or primers.

[0070] Recombinant DNA Molecules and Host-Vector Systems

[0071] The invention also provides recombinant DNA or RNA molecules containing a STEAP polynucleotide, including but not limited to phages, plasmids, phagemids, cosmids, YAC's, BAC's, as well as various viral and non-viral vectors well known in the art, and cells transformed or transfected with such recombinant DNA or RNA molecules. As used herein, a recombinant DNA or RNA molecule is a DNA or RNA molecule that has been subjected to molecular manipulation in vitro. Methods for generating such molecules are well known (see, for example, Sambrook, et al. (1989) supra).

[0072] The invention further provides a host-vector system comprising a recombinant DNA molecule containing a STEAP polynucleotide within a suitable prokaryotic or eukaryotic host cell. Examples of suitable eukaryotic host cells include a yeast cell, a plant cell, or an animal cell, such as a mammalian cell or an insect cell (e.g., a baculovirus-infectible cell such as an Sf9 cell). Examples of suitable mammalian cells include various prostate cancer cell lines such LnCaP, PC-3, DU145, LAPC-4, TsuPr1, other transfectable or transducible prostate cancer cell lines, as well as a number of mammalian cells routinely used for the expression of recombinant proteins (e.g., COS, CHO, 293, 293T cells). More particularly, a polynucleotide comprising the coding sequence of a STEAP may be used to generate STEAP proteins or fragments thereof using any number of host-vector systems routinely used and widely known in the art.

[0073] A wide range of host-vector systems suitable for the expression of STEAP proteins or fragments thereof are available, see, for example, Sambrook, et al. (1989) supra; Current Protocols in Molecular Biology (1995) supra). Preferred vectors for mammalian expression include but are not limited to pcDNA 3.1 myC-His-tag (Invitrogen) and the retroviral vector pSRαtkneo (Muller, A. J., et al., Mol. Cell. Biol. (1991) 11:1785). Using these expression vectors, STEAP may be preferably expressed in several prostate cancer and non-prostate cell lines, including for example 293, 293T, rat-1, 3T3, PC-3, LNCaP and TsuPr1. The host-vector systems of the invention are useful for the production of a STEAP protein or fragment thereof. Such host-vector systems may be employed to study the functional properties of STEAP and STEAP mutations.

[0074] Proteins encoded by the STEAP genes, or by fragments thereof, will have a variety of uses, including but not limited to generating antibodies and in methods for identifying ligands and other agents and cellular constituents that bind to a STEAP gene product. Antibodies raised against a STEAP protein or fragment thereof may be useful in diagnostic and prognostic assays, imaging methodologies (including, particularly, cancer imaging), and therapeutic methods in the management of human cancers characterized by expression of a STEAP protein, such as prostate, colon, breast, cervical and bladder carcinomas, ovarian cancers, testicular cancers and pancreatic cancers. Various immunological assays useful for the detection of STEAP proteins are contemplated, including but not limited to various types of radioimmunoassays, enzyme-linked immunosorbent assays (ELISA), enzyme-linked immunofluorescent assays (ELIFA), immunocytochemical methods, and the like. Such antibodies may be labeled and used as immunological imaging reagents capable of detecting prostate cells (e.g., in radioscintigraphic imaging methods). STEAP proteins may also be particularly useful in generating cancer vaccines, as further described below.

[0075] STEAP Proteins

[0076] Another aspect of the present invention provides various STEAP proteins and polypeptide fragments thereof. As used herein, a STEAP protein refers to a protein that has or includes the amino acid sequence of human STEAP-1 as provided in FIG. 1A, human STEAP-2 as provided in FIG. 9, human STEAP-3 as provided in FIG. 10A, the amino acid sequence of other mammalian STEAP homologues (e.g., STEAP-4) and variants, as well as allelic variants and conservative substitution mutants of these proteins that have STEAP biological activity.

[0077] The STEAP proteins of the invention include those specifically identified herein, as well as allelic variants, conservative substitution variants and homologs that can be isolated/generated and characterized without undue experimentation following the methods outlined below. Fusion proteins which combine parts of different STEAP proteins or fragments thereof, as well as fusion proteins of a STEAP protein and a heterologous polypeptide are also included. Such STEAP proteins will be collectively referred to as the STEAP proteins, the proteins of the invention, or STEAP. As used herein, the term “STEAP polypeptide” refers to a polypeptide fragment or a STEAP protein of at least 8 amino acids, preferably at least 10 amino acids.

[0078] A specific embodiment of a STEAP protein comprises a polypeptide having the amino acid sequence of human STEAP-1 as shown in FIG. 1A. Another embodiment of a STEAP protein comprises a polypeptide containing the STEAP-2 amino acid sequence as shown in FIG. 9. Another embodiment comprises a polypeptide containing the STEAP-3 amino acid sequence of shown in FIG. 10A. Yet another embodiment comprises a polypeptide containing the partial STEAP-4 amino acid sequence of shown in FIG. 11A.

[0079] In general, naturally occurring allelic variants of individual human STEAP's will share a high degree of structural identity and homology (e.g., 90% or more identity). Typically, allelic variants of the STEAP proteins will contain conservative amino acid substitutions within the STEAP sequences described herein or will contain a substitution of an amino acid from a corresponding position in a STEAP homologue. One class of STEAP allelic variants will be proteins that share a high degree of homology with at least a small region of a particular STEAP amino acid sequence, but will further contain a radical departure form the sequence, such as a non-conservative substitution, truncation, insertion or frame shift. Such alleles may represent mutant STEAP proteins that typically do not perform the same biological functions or do not have all of the biological characteristics.

[0080] Conservative amino acid substitutions can frequently be made in a protein without altering either the conformation or the function of the protein. Such changes include substituting any of isoleucine (I), valine (V), and leucine (L) for any other of these hydrophobic amino acids; aspartic acid (D) for glutamic acid (E) and vice versa; glutamine (Q) for asparagine (N) and vice versa; and serine (S) for threonine (T) and vice versa. Other substitutions can also be considered conservative, depending on the environment of the particular amino acid and its role in the three-dimensional structure of the protein. For example, glycine (G) and alanine (A) can frequently be interchangeable, as can alanine (A) and valine (V). Methionine (M), which is relatively hydrophobic, can frequently be interchanged with leucine and isoleucine, and sometimes with valine. Lysine (K) and arginine (R) are frequently interchangeable in locations in which the significant feature of the amino acid residue is its charge and the differing pK's of these two amino acid residues are not significant. Still other changes can be considered “conservative” in particular environments.

[0081] STEAP proteins may be embodied in many forms, preferably in isolated form. As used herein, a protein is said to be “isolated” when physical, mechanical or chemical methods are employed to remove the STEAP protein from cellular constituents that are normally associated with the protein. A skilled artisan can readily employ standard purification methods to obtain an isolated STEAP protein. A purified STEAP protein molecule will be substantially free of other proteins or molecules which impair the binding of STEAP to antibody or other ligand. The nature and degree of isolation and purification will depend on the intended use. Embodiments of a STEAP protein include a purified STEAP protein and a functional, soluble STEAP protein. In one form, such functional, soluble STEAP proteins or fragments thereof retain the ability to bind antibody or other ligand.

[0082] The invention also provides STEAP polypeptides comprising biologically active fragments of the STEAP amino acid sequence, such as a polypeptide corresponding to part of the amino acid sequences for STEAP-1 as shown in FIG. 1A, STEAP-2 as shown in FIG. 9, STEAP-3 as shown in FIG. 10A, or STEAP-4 as shown in FIG. 11A. Such polypeptides of the invention exhibit properties of a STEAP protein, such as the ability to elicit the generation of antibodies which specifically bind an epitope associated with a STEAP protein. Polypeptides comprising amino acid sequences which are unique to a particular STEAP protein (relative to other STEAP proteins) may be used to generate antibodies which will specifically react with that particular STEAP protein. For example, referring to the amino acid alignment of the STEAP structures shown in FIGS. 11A-11D, the skilled artisan will readily appreciate that each molecule contains stretches of sequence unique to its structure. These unique stretches can be used to generate antibodies specific to a particular STEAP. Similarly, regions of conserved sequence may be used to generate antibodies that may bind to multiple STEAP's.

[0083] STEAP polypeptides can be generated using standard peptide synthesis technology or using chemical cleavage methods well known in the art based on the amino acid sequences of the human STEAP proteins disclosed herein. Alternatively, recombinant methods can be used to generate nucleic acid molecules that encode a polypeptide fragment of a STEAP protein. In this regard, the STEAP-encoding nucleic acid molecules described herein provide means for generating defined polypeptide fragments of STEAP proteins. Such STEAP polypeptides or peptides are particularly useful for generating and characterizing domain specific antibodies (e.g., antibodies recognizing an extracellular or intracellular epitope of a STEAP protein), generating STEAP family member specific antibodies (e.g., anti-STEAP-1, anti-STEAP-2 antibodies), identifying agents or cellular factors that bind to a particular STEAP or STEAP domain, and in various therapeutic contexts, including but not limited to cancer vaccines. STEAP polypeptides containing particularly interesting structures can be predicted and/or identified using various analytical techniques well known in the art, including, for example, the methods of Chou-Fasman, Garnier-Robson, Kyte-Doolittle, Eisenberg, Karplus-Schultz or Jameson-Wolf analysis, or on the basis of immunogenicity. Fragments containing such structures are particularly useful in generating subunit specific anti-STEAP antibodies or in identifying cellular factors that bind to STEAP.

[0084] STEAP Antibodies.

[0085] Another aspect of the invention provides antibodies that bind to STEAP proteins and polypeptides. The most preferred antibodies will specifically bind to a STEAP protein and will not bind (or will bind weakly) to non-STEAP proteins and polypeptides. Anti-STEAP antibodies that are particularly contemplated include monoclonal and polyclonal antibodies as well as fragments containing the antigen binding domain and/or one or more complementarity determining regions of these antibodies. As used herein, an antibody fragment is defined as at least a portion of the variable region of the immunoglobulin molecule which binds to its target, i.e., the antigen binding region.

[0086] For some applications, it may be desirable to generate antibodies which specifically react with a particular STEAP protein and/or an epitope within a particular structural domain. For example, preferred antibodies useful for cancer therapy and diagnostic imaging purposes are those which react with an epitope in an extracellular region of the STEAP protein as expressed in cancer cells. Such antibodies may be generated by using the STEAP proteins described herein, or using peptides derived from predicted extracellular domains thereof, as an immunogen. In this regard, with reference to the STEAP-1 protein topological schematic shown in FIG. 1B, regions in the extracellular loops between the indicated transmembrane domains may be selected as used to design appropriate immunogens for raising extracellular-specific antibodies.

[0087] STEAP antibodies of the invention may be particularly useful in prostate cancer therapeutic strategies, diagnostic and prognostic assays, and imaging methodologies. The invention provides various immunological assays useful for the detection and quantification of STEAP and mutant STEAP proteins and polypeptides. Such assays generally comprise one or more STEAP antibodies capable of recognizing and binding a STEAP or mutant STEAP protein, as appropriate, and may be performed within various immunological assay formats well known in the art, including but not limited to various types of radioimmunoassays, enzyme-linked immunosorbent assays (ELISA), enzyme-linked immunofluorescent assays (ELIFA), and the like. In addition, immunological imaging methods capable of detecting prostate cancer are also provided by the invention, including but limited to radioscintigraphic imaging methods using labeled STEAP antibodies. Such assays may be clinically useful in the detection, monitoring, and prognosis of prostate cancer, particularly advanced prostate cancer.

[0088] The invention also provides various immunological assays useful for the detection and quantification of STEAP and mutant STEAP proteins and polypeptides. Such assays generally comprise one or more STEAP antibodies capable of recognizing and binding a STEAP or mutant STEAP protein, as appropriate, and may be performed within various immunological assay formats well known in the art, including but not limited to various types of radioimmunoassays, enzyme-linked immunosorbent assays (ELISA), enzyme-linked immunofluorescent assays (ELIFA), and the like. In addition, immunological imaging methods capable of detecting prostate cancer and other cancers expressing STEAP (e.g., breast cancer) are also provided by the invention, including but limited to radioscintigraphic imaging methods using labeled STEAP antibodies. Such assays may be clinically useful in the detection, monitoring, and prognosis of STEAP expressing cancers such as prostate cancer.

[0089] STEAP antibodies may also be used in methods for purifying STEAP and mutant STEAP proteins and polypeptides and for isolating STEAP homologues and related molecules. For example, in one embodiment, the method of purifying a STEAP protein comprises incubating a STEAP antibody, which has been coupled to a solid matrix, with a lysate or other solution containing STEAP under conditions which permit the STEAP antibody to bind to STEAP; washing the solid matrix to eliminate impurities; and eluting the STEAP from the coupled antibody. Other uses of the STEAP antibodies of the invention include generating anti-idiotypic antibodies that mimic the STEAP protein.

[0090] Various methods for the preparation of antibodies are well known in the art. For example, antibodies may be prepared by immunizing a suitable mammalian host using a STEAP protein, peptide, or fragment, in isolated or immunoconjugated form (Antibodies: A Laboratory Manual, CSH Press, Eds., Harlow, and Lane (1988); Harlow, Antibodies, Cold Spring Harbor Press, NY (1989)). In addition, fusion proteins of STEAP may also be used, such as a STEAP GST-fusion protein. In a particular embodiment, a GST fusion protein comprising all or most of the open reading frame amino acid sequence of a STEAP may be produced and used as an immunogen to generate appropriate antibodies. In another embodiment, a STEAP peptide may be synthesized and used as an immunogen. As described in Example 5, below, the 15-mer STEAP peptide HSSKEKLRRERIKYC was conjugated to keyhole limpet hemocyanin (KLH) and used to immunize a rabbit. The resulting polyclonal antiserum specifically recognized STEAP expressed in a recombinant mammalian expression system.

[0091] In addition, naked DNA immunization techniques known in the art may be used (with or without purified STEAP protein or STEAP expressing cells) to generate an immune response to the encoded immunogen (for review, see Donnelly, et al., Ann. Rev. Immunol. (1997) 15:617-648).

[0092] The amino acid sequences of the STEAP's provided herein may be used to select specific regions of the STEAP protein for generating antibodies. For example, hydrophobicity and hydrophilicity analyses of the STEAP amino acid sequence may be used to identify hydrophilic regions in the STEAP structure. Regions of the STEAP protein that show immunogenic structure, as well as other regions and domains, can readily be identified using various other methods known in the art, such as Chou-Fasman, Gamier-Robson, Kyte-Doolittle, Eisenberg, Karplus-Schultz or Jameson-Wolf analysis. Methods for the generation of STEAP antibodies are further illustrated by way of the examples provided herein.

[0093] Methods for preparing a protein or polypeptide for use as an immunogen and for preparing immunogenic conjugates of a protein with a carrier such as BSA, KLH, or other carrier proteins are well known in the art. In some circumstances, direct conjugation using, for example, carbodiimide reagents may be used; in other instances linking reagents such as those supplied by Pierce Chemical Co., Rockford, Ill., may be effective. Administration of a STEAP immunogen is conducted generally by injection over a suitable time period and with use of a suitable adjuvant, as is generally understood in the art. During the immunization schedule, titers of antibodies can be taken to determine adequacy of antibody formation.

[0094] STEAP monoclonal antibodies are preferred and may be produced by various means well known in the art. For example, immortalized cell lines which secrete a desired monoclonal antibody may be prepared using the standard hybridoma technology of Kohler and Milstein or modifications which immortalize producing B cells, as is generally known. The immortalized cell lines secreting the desired antibodies are screened by immunoassay in which the antigen is the STEAP protein or a STEAP fragment. When the appropriate immortalized cell culture secreting the desired antibody is identified, the cells may be expanded and antibodies produced either from in vitro cultures or from ascites fluid.

[0095] The antibodies or fragments may also be produced, using current technology, by recombinant means. Regions that bind specifically to the desired regions of the STEAP protein can also be produced in the context of chimeric or CDR grafted antibodies of multiple species origin. Humanized or human STEAP antibodies may also be produced and are preferred for use in therapeutic contexts. Methods for humanizing murine and other non-human antibodies by substituting one or more of the non-human antibody CDR's for corresponding human antibody sequences are well known (see, for example, Jones, et al., Nature (1986) 321:522-525; Reichmann, et al., Nature (1988) 332:323-327; Verhoeyan, et al., Science (1988) 239:1534-1536). See also, Carter, et al., Proc. Natl. Acad. Sci. USA (1993) 89:4285 and Sims, et al., J. Immunol. (1993) 151:2296. Methods for producing fully human monoclonal antibodies include phage display and transgenic methods (for review, see Vaughan, et al., Nature Biotechnology (1998) 16:535-539).

[0096] Fully human STEAP monoclonal antibodies may be generated using cloning technologies employing large human Ig gene combinatorial libraries (i.e., phage display) (Griffiths and Hoogenboom, “Building an in vitro immune system: human antibodies from phage display libraries.” In: Protein Engineering of Antibody Molecules for Prophylactic and Therapeutic Applications in Man. Clark, M. (Ed.), Nottingham Academic, pp. 45-64 (1993); Burton and Barbas, “Human Antibodies from combinatorial libraries.” Id., pp. 65-82). Fully human STEAP monoclonal antibodies may also be produced using transgenic mice engineered to contain human immunoglobulin gene loci as described in PCT Patent Application WO 98/24893, Kucherlapati, R., and Jakobovits, A., et al., published Dec. 3, 1997 (see also, Jakobovits, A., Exp. Opin. Invest. Drugs (1998) 7:607-614). This method avoids the in vitro manipulation required with phage display technology and efficiently produces high affinity authentic human antibodies.

[0097] Reactivity of STEAP antibodies with a STEAP protein may be established by a number of well known means, including Western blot, immunoprecipitation, ELISA, and FACS analyses using, as appropriate, STEAP proteins, peptides, STEAP-expressing cells or extracts thereof.

[0098] A STEAP antibody or fragment thereof of the invention may be labeled with a detectable marker or conjugated to a second molecule. Suitable detectable markers include, but are not limited to, a radioisotope, a fluorescent compound, a bioluminescent compound, chemiluminescent compound, a metal chelator or an enzyme. Further, bi-specific antibodies specific for two or more STEAP epitopes may be generated using methods generally known in the art. Homodimeric antibodies may also be generated by cross-linking techniques known in the art (e.g., Wolff, E. A., et al., Cancer Res. (1993) 53:2560-2565).

[0099] Methods for the Detection of STEAP

[0100] Another aspect of the present invention relates to methods for detecting STEAP polynucleotides and STEAP proteins, as well as methods for identifying a cell which expresses STEAP.

[0101] More particularly, the invention provides assays for the detection of STEAP polynucleotides in a biological sample, such as serum, bone, prostate, and other tissues, urine, semen, cell preparations, and the like. Detectable STEAP polynucleotides include, for example, a STEAP gene or fragments thereof, STEAP mRNA, alternative splice variant STEAP mRNA's, and recombinant DNA or RNA molecules containing a STEAP polynucleotide. A number of methods for amplifying and/or detecting the presence of STEAP polynucleotides are well known in the art and may be employed in the practice of this aspect of the invention.

[0102] In one embodiment, a method for detecting a STEAP mRNA in a biological sample comprises producing cDNA from the sample by reverse transcription using at least one primer; amplifying the cDNA so produced using a STEAP polynucleotides as sense and antisense primers to amplify STEAP cDNA's therein; and detecting the presence of the amplified STEAP cDNA. In another embodiment, a method of detecting a STEAP gene in a biological sample comprises first isolating genomic DNA from the sample; amplifying the isolated genomic DNA using STEAP polynucleotides as sense and antisense primers to amplify the STEAP gene therein; and detecting the presence of the amplified STEAP gene. Any number of appropriate sense and antisense probe combinations may be designed from the nucleotide sequences provided for STEAP-1 (FIG. 1A), STEAP-2 (FIG. 9), STEAP-3 (FIG. 10A), or STEAP-4 (FIG. 10B), as appropriate, and used for this purpose.

[0103] The invention also provides assays for detecting the presence of a STEAP protein in a tissue of other biological sample such as serum, bone, prostate, and other tissues, urine, cell preparations, and the like. Methods for detecting a STEAP protein are also well known and include, for example, immunoprecipitation, immunohistochemical analysis, Western Blot analysis, molecular binding assays, ELISA, ELIFA and the like.

[0104] For example, in one embodiment, a method of detecting the presence of a STEAP protein in a biological sample comprises first contacting the sample with a STEAP antibody, a STEAP-reactive fragment thereof, or a recombinant protein containing an antigen binding region of a STEAP antibody; and then detecting the binding of STEAP protein in the sample thereto.

[0105] Methods for identifying a cell which expresses STEAP are also provided. In one embodiment, an assay for identifying a cell which expresses a STEAP gene comprises detecting the presence of STEAP mRNA in the cell. Methods for the detection of particular mRNA's in cells are well known and include, for example, hybridization assays using complementary DNA probes (such as in situ hybridization using labeled STEAP riboprobes, Northern blot and related techniques) and various nucleic acid amplification assays (such as RT-PCR using complementary primers specific for STEAP, and other amplification type detection methods, such as, for example, branched DNA, SISBA, TMA and the like). Alternatively, an assay for identifying a cell which expresses a STEAP gene comprises detecting the presence of STEAP protein in the cell or secreted by the cell. Various methods for the detection of proteins are well known in the art and may be employed for the detection of STEAP proteins and STEAP expressing cells.

[0106] STEAP expression analysis may also be useful as a tool for identifying and evaluating agents which modulate STEAP gene expression. For example, STEAP-1 expression is significantly upregulated in colon, bladder, pancreatic, ovarian and other cancers. Identification of a molecule or biological agent that could inhibit STEAP-1 over-expression may be of therapeutic value in the treatment of cancer. Such an agent may be identified by using a screen that quantifies STEAP expression by RT-PCR, nucleic acid hybridization or antibody binding.

[0107] Assays for Determining STEAP Expression Status

[0108] Determining the status of STEAP expression patterns in an individual may be used to diagnose cancer and may provide prognostic information useful in defining appropriate therapeutic options. Similarly, the expression status of STEAP may provide information useful for predicting susceptibility to particular disease stages, progression, and/or tumor aggressiveness. The invention provides methods and assays for determining STEAP expression status and diagnosing cancers which express STEAP.

[0109] In one aspect, the invention provides assays useful in determining the presence of cancer in an individual, comprising detecting a significant increase in STEAP mRNA or protein expression in a test cell or tissue sample relative to expression levels in the corresponding normal cell or tissue. In one embodiment, the presence of STEAP-1 mRNA is evaluated in tissue samples of the colon, pancreas, bladder, ovary, cervix, testis or breast. The presence of significant STEAP-1 expression in any of these tissues may be useful to indicate the emergence, presence and/or severity of these cancers, since the corresponding normal tissues do not express STEAP-1 mRNA. In a related embodiment, STEAP-1 expression status may be determined at the protein level rather than at the nucleic acid level. For example, such a method or assay would comprise determining the level of STEAP-1 protein expressed by cells in a test tissue sample and comparing the level so determined to the level of STEAP expressed in a corresponding normal sample. In one embodiment, the presence of STEAP-1 protein is evaluated, for example, using immunohistochemical methods. STEAP antibodies or binding partners capable of detecting STEAP protein expression may be used in a variety of assay formats well known in the art for this purpose.

[0110] Peripheral blood may be conveniently assayed for the presence of cancer cells, including prostate, colon, pancreatic, bladder and ovarian cancers, using RT-PCR to detect STEAP-1 expression. The presence of RT-PCR amplifiable STEAP-1 mRNA provides an indication of the presence of one of these types of cancer. RT-PCR detection assays for tumor cells in peripheral blood are currently being evaluated for use in the diagnosis and management of a number of human solid tumors. In the prostate cancer field, these include RT-PCR assays for the detection of cells expressing PSA and PSM (Verkaik, N. S., et al., Urol. Res. (1997) 25:373-384; Ghossein, R. A., et al., J. Clin. Oncol. (1995) 13:1195-2000; Heston, W. D., et al., Clin. Chem. (1995) 41:1687-1688). RT-PCR assays are well known in the art.

[0111] In another approach, a recently described sensitive assay for detecting and characterizing carcinoma cells in blood may be used (Racila, E., et al., Proc. Natl. Acad. Sci. USA (1998) 95:4589-4594). This assay combines immunomagnetic enrichment with multiparameter flow cytometric and immunohistochemical analyses, and is highly sensitive for the detection of cancer cells in blood, reportedly capable of detecting one epithelial cell in 1 ml of peripheral blood.

[0112] A related aspect of the invention is directed to predicting susceptibility to developing cancer in an individual. In one embodiment, a method for predicting susceptibility to cancer comprises detecting STEAP mRNA or STEAP protein in a tissue sample, its presence indicating susceptibility to cancer, wherein the degree of STEAP mRNA expression present is proportional to the degree of susceptibility.

[0113] Yet another related aspect of the invention is directed to methods for gauging tumor aggressiveness. In one embodiment, a method for gauging aggressiveness of a tumor comprises determining the level of STEAP mRNA or STEAP protein expressed by cells in a sample of the tumor, comparing the level so determined to the level of STEAP mRNA or STEAP protein expressed in a corresponding normal tissue taken from the same individual or a normal tissue reference sample, wherein the degree of STEAP mRNA or STEAP protein expression in the tumor sample relative to the normal sample indicates the degree of aggressiveness.

[0114] Methods for detecting and quantifying the expression of STEAP mRNA or protein are described herein and use standard nucleic acid and protein detection and quantification technologies well known in the art. Standard methods for the detection and quantification of STEAP mRNA include in situ hybridization using labeled STEAP riboprobes, Northern blot and related techniques using STEAP polynucleotide probes, RT-PCR analysis using primers specific for STEAP, and other amplification type detection methods, such as, for example, branched DNA, SISBA, TMA and the like. In a specific embodiment, semi-quantitative RT-PCR may be used to detect and quantify STEAP mRNA expression as described in the Examples which follow. Any number of primers capable of amplifying STEAP may be used for this purpose, including but not limited to the various primer sets specifically described herein. Standard methods for the detection and quantification of protein may be used for this purpose. In a specific embodiment, polyclonal or monoclonal antibodies specifically reactive with the wild-type STEAP protein may be used in an immunohistochemical assay of biopsied tissue.

[0115] Diagnostic Imaging of Human Cancers

[0116] Antibodies specific for STEAP's may be particularly useful in radionuclide and other forms of diagnostic imaging of certain cancers, given their expression profiles and cell surface location. For example, immunohistochemical analysis of STEAP-1 protein suggests that in normal tissues STEAP-1 is predominantly restricted to prostate and bladder. The transmembrane orientation of STEAP-1 (and presumably STEAP-2, STEAP-3, STEAP-4) provides a target readily identifiable by antibodies specifically reactive with extracellular epitopes. This tissue restricted expression, and the localization of STEAP to the cell surface of multiple cancers makes STEAP an ideal candidate for diagnostic imaging. Accordingly, in vivo imaging techniques may be used to image human cancers expressing a STEAP protein.

[0117] For example, cell surface STEAP-1 protein is expressed at very high levels in several human cancers, particularly prostate, bladder, colon and ovarian cancers, and Ewing sarcoma. Moreover, in normal tissues, STEAP-1 protein expression is largely restricted to prostate. Thus, radiolabeled antibodies specifically reactive with extracellular epitopes of STEAP-1 may be particularly useful in vivo imaging of solid tumors of the foregoing cancers. Such labeled anti-STEAP-1 antibodies may provide very high level sensitivities for the detection of metastasis of these cancers.

[0118] Preferably, monoclonal antibodies are used in the diagnostic imaging methods of the invention.

[0119] Cancer Immunotherapy and Cancer Vaccines

[0120] The invention provides various immunotherapeutic methods for treating prostate cancer, including antibody therapy, in vivo vaccines, and ex vivo immunotherapy methods, which utilize polynucleotides and polypeptides corresponding to STEAP and STEAP antibodies. These therapeutic applications are described further in the following subsections.

[0121] Antibody Therapy

[0122] The cell surface nature and expression profiles of the STEAP's in cancers including prostate cancer indicate that they are promising targets for antibody therapy of prostate and other cancers expressing STEAP's. The experimental results described in the Examples herein provide compelling evidence that STEAP-1 is strongly expressed uniformly over the surface of glandular epithelial cells within prostate and prostate cancer cells. In particular, immunohistochemical analysis results show that the surface of human prostate epithelial cells (normal and cancer) appear to be uniformly coated with STEAP-1. Biochemical analysis confirms the cell surface localization of STEAP-1 initially suggested by its putative 6-transmembrane primary structural elements and by the pericellular staining plainly visualized by immunohistochemical staining.

[0123] STEAP-1 is uniformly expressed at high levels over the surface of prostate glandular epithelia, an ideal situation for immunotherapeutic intervention strategies which target extracellular STEAP epitopes. Systemic administration of STEAP-immunoreactive compositions would be expected to result in extensive contact of the composition with prostate epithelial cells via binding to STEAP-1 extracellular epitopes. Moreover, given the near absence of STEAP-1 protein expression in normal human tissues, there is ample reason to expect exquisite sensitivity without toxic, non-specific and/or non-target effects caused by the binding of the immunotherapeutic composition to STEAP-1 on non-target organs and tissues.

[0124] In addition to the high level expression of STEAP-1 in prostate and prostate cancer cells, STEAP-1 appears to be substantially over-expressed in a variety of other human cancers, including bladder, colon, pancreatic and ovarian cancers. In particular, high level STEAP-1 mRNA expression is detected in all tested prostate cancer tissues and cell lines, and in most of the pancreatic, colon, and bladder cancer cell lines tested. High level expression of STEAP-1 is also observed in some ovarian cancer cell lines. Lower level expression is observed in some breast, testicular, and cervical cancer cell lines. Very high level expression is also detected in a Ewing sarcoma cell line. Applicants have shown that cell surface STEAP-1 protein is expressed in bladder and colon cancers, while there is no detectable cell surface (or intracellular) STEAP-1 protein in normal colon and low expression in normal bladder. Antibodies specifically reactive with extracellular domains of STEAP-1 may be useful to treat these cancers systemically, either as toxin or therapeutic agent conjugates or as naked antibodies capable of inhibiting cell proliferation or function.

[0125] STEAP-2 protein is also expressed in prostate cancer, and may be expressed in other cancers as well. STEAP-2 mRNA analysis by RT-PCR and Northern blot show that expression is restricted to prostate in normal tissues, is also expressed in some prostate, pancreatic, colon, testicular, ovarian and other cancers. Therefore, antibodies reactive with STEAP-2 may be useful in the treatment of prostate and other cancers. Similarly, although not yet characterized by applicants, the expression of STEAP-3 and STEAP-4 (as well as other STEAP's) may be associated with some cancers. Thus antibodies reactive with these STEAP family member proteins may also be useful therapeutically.

[0126] STEAP antibodies may be introduced into a patient such that the antibody binds to STEAP on the cancer cells and mediates the destruction of the cells and the tumor and/or inhibits the growth of the cells or the tumor. Mechanisms by which such antibodies exert a therapeutic effect may include complement-mediated cytolysis, antibody-dependent cellular cytotoxicity, modulating the physiologic function of STEAP, inhibiting ligand binding or signal transduction pathways, modulating tumor cell differentiation, altering tumor angiogenesis factor profiles, and/or by inducing apoptosis. STEAP antibodies conjugated to toxic or therapeutic agents may also be used therapeutically to deliver the toxic or therapeutic agent directly to STEAP-bearing tumor cells.

[0127] Cancer therapy using anti-STEAP antibodies may follow the teachings generated from various approaches which have been successfully employed with respect to other types of cancer, including but not limited to colon cancer (Arlen, et al., Crit Rev Immunol (1998) 18:133-138), multiple myeloma (Ozaki, S., et al., Blood (1997) 90:3179-3186; Tsunenari, T., et al., Blood (1997) 90:2437-2444), gastric cancer (Kasprzyk, P. G., et al., Cancer Res. (1992) 52:2771-2776), B-cell lymphoma (Funakoshi, S., et al., J. Immunother. (1996) 19:93-101), leukemia (Zhong, R., et al., Leuk. Res. (1996) 20:581-589), colorectal cancer (Mount, P. F., et al., Cancer Res. (1994) 54:6160-6166); Velders, M. P., et al., Cancer Res. (1995) 55:4398-4403), and breast cancer (Shepard, H. M., et al., J. Clin. Immunol. (1991) 11:117-127).

[0128] Although STEAP antibody therapy may be useful for all stages of the foregoing cancers, antibody therapy may be particularly appropriate and in advanced or metastatic cancers. Combining the antibody therapy method of the invention with a chemotherapeutic or radiation regimen may be preferred in patients who have not received chemotherapeutic treatment, whereas treatment with the antibody therapy of the invention may be indicated for patients who have received one or more chemotherapy. Additionally, antibody therapy may also enable the use of reduced dosages of concomitant chemotherapy, particularly in patients that do not tolerate the toxicity of the chemotherapeutic agent very well.

[0129] It may be desirable for non-prostate cancer patients to be evaluated for the presence and level of STEAP over-expression, preferably using immunohistochemical assessments of tumor tissue, quantitative STEAP imaging, or other techniques capable of reliably indicating the presence and degree of STEAP overexpression. Immunohistochemical analysis of tumor biopsies or surgical specimens may be preferred for this purpose. Methods for immunohistochemical analysis of tumor tissues are well known in the art.

[0130] Anti-STEAP monoclonal antibodies useful in treating prostate and other cancers include those which are capable of initiating a potent immune response against the tumor and those which are capable of direct cytotoxicity. In this regard, anti-STEAP mAb's may elicit tumor cell lysis by either complement-mediated or antibody-dependent cell cytotoxicity (ADCC) mechanisms, both of which require an intact Fc portion of the immunoglobulin molecule for interaction with effector cell Fc receptor sites or complement proteins. In addition, anti-STEAP mAb's which exert a direct biological effect on tumor growth are useful in the practice of the invention. Potential mechanisms by which such directly cytotoxic mAb's may act include inhibition of cell growth, modulation of cellular differentiation, modulation of tumor angiogenesis factor profiles, and the induction of apoptosis. The mechanism by which a particular anti-STEAP mAb exerts an anti-tumor effect may be evaluated using any number of in vitro assays designed to determine ADCC, ADMMC, complement-mediated cell lysis, and so forth, as is generally known in the art.

[0131] The anti-tumor activity of a particular anti-STEAP mAb, or combination of anti-STEAP mAb's, may be evaluated in vivo using a suitable animal model. For example, xenogenic prostate cancer models wherein human prostate cancer explants or passaged xenograft tissues are introduced into immune compromised animals, such as nude or SCID mice, are appropriate in relation to prostate cancer and have been described (Klein, et al., Nature Medicine (1997) 3:402-408). For Example, PCT Patent Application WO 98/16628, Sawyers, et al., published Apr. 23, 1998, describes various xenograft models of human prostate cancer capable of recapitulating the development of primary tumors, micrometastasis, and the formation of osteoblastic metastases characteristic of late stage disease. Efficacy may be predicted using assays which measure inhibition of tumor formation, tumor regression or metastasis, and the like.

[0132] It should be noted that the use of murine or other non-human monoclonal antibodies, human/mouse chimeric mAb's may induce moderate to strong immune responses in some patients. In the most severe cases, such an immune response may lead to the extensive formation of immune complexes which, potentially, can cause renal failure. Accordingly, preferred monoclonal antibodies used in the practice of the therapeutic methods of the invention are those which are either fully human or humanized and which bind specifically to the target 20P1F12/TMPRSS2 antigen with high affinity but exhibit low or no antigenicity in the patient.

[0133] The method of the invention contemplates the administration of single anti-STEAP mAb's as well as combinations, or “cocktails,” of different mAb's. Such mAb cocktails may have certain advantages inasmuch as they contain mAb's which exploit different effector mechanisms or combine directly cytotoxic mAb's with mAb's that rely on immune effector functionality. Such mAb's in combination may exhibit synergistic therapeutic effects. In addition, the administration of anti-STEAP mAb's may be combined with other therapeutic agents, including but not limited to various chemotherapeutic agents, androgen-blockers, and immune modulators (e.g., IL-2, GM-CSF). The anti-STEAP mAb's may be administered in their “naked” or unconjugated form, or may have therapeutic agents conjugated to them.

[0134] The anti-STEAP monoclonal antibodies used in the practice of the method of the invention may be formulated into pharmaceutical compositions comprising a carrier suitable for the desired delivery method. Suitable carriers include any material which when combined with the anti-STEAP mAb's retains the anti-tumor function of the antibody and is non-reactive with the subject's immune systems. Examples include, but are not limited to, any of a number of standard pharmaceutical carriers such as sterile phosphate buffered saline solutions, bacteriostatic water, and the like.

[0135] The anti-STEAP antibody formulations may be administered via any route capable of delivering the antibodies to the tumor site. Potentially effective routes of administration include, but are not limited to, intravenous, intraperitoneal, intramuscular, intratumoral, intradermal, and the like. The preferred route of administration is by intravenous injection. A preferred formulation for intravenous injection comprises the anti-STEAP mAb's in a solution of preserved bacteriostatic water, sterile unpreserved water, and/or diluted in polyvinylchloride or polyethylene bags containing 0.9/o sterile Sodium Chloride for Injection, USP. The anti-STEAP mAb preparation may be lyophilized and stored as a sterile powder, preferably under vacuum, and then reconstituted in bacteriostatic water containing, for example, benzyl alcohol preservative, or in sterile water prior to injection.

[0136] Treatment will generally involve the repeated administration of the anti-STEAP antibody preparation via an acceptable route of administration such as intravenous injection (IV), typically at a dose in the range of about 0.1 to about 10 mg/kg body weight. Doses in the range of 10-500 mg mAb per week may be effective and well tolerated. Based on clinical experience with the Herceptin® mAb in the treatment of metastatic breast cancer, an initial loading dose of approximately 4 mg/kg patient body weight IV followed by weekly doses of about 2 mg/kg IV of the anti-STEAP mAb preparation may represent an acceptable dosing regimen. Preferably, the initial loading dose is administered as a 90 minute or longer infusion. The periodic maintenance dose may be administered as a 30 minute or longer infusion, provided the initial dose was well tolerated. However, as one of skill in the art will understand, various factors will influence the ideal dose regimen in a particular case. Such factors may include, for example, the binding affinity and half life of the mAb or mAb's used, the degree of STEAP overexpression in the patient, the extent of circulating shed STEAP antigen, the desired steady-state antibody concentration level, frequency of treatment, and the influence of chemotherapeutic agents used in combination with the treatment method of the invention.

[0137] Optimally, patients should be evaluated for the level of circulating shed STEAP antigen in serum in order to assist in the determination of the most effective dosing regimen and related factors. Such evaluations may also be used for monitoring purposes throughout therapy, and may be useful to gauge therapeutic success in combination with evaluating other parameters (such as serum PSA levels in prostate cancer therapy).

[0138] Cancer Vaccines

[0139] The invention further provides prostate cancer vaccines comprising a STEAP protein or fragment thereof. The use of a tumor antigen in a vaccine for generating humoral and cell-mediated immunity for use in anti-cancer therapy is well known in the art and has been employed in prostate cancer using human PSMA and rodent PAP immunogens (Hodge, et al., Int. J. Cancer (1995) 63:231-237; Fong, et al., J. Immunol. (1997) 159:3113-3117). Such methods can be readily practiced by employing a STEAP protein, or fragment thereof, or a STEAP-encoding nucleic acid molecule and recombinant vectors capable of expressing and appropriately presenting the STEAP immunogen.

[0140] For example, viral gene delivery systems may be used to deliver a STEAP-encoding nucleic acid molecule. Various viral gene delivery systems which can be used in the practice of this aspect of the invention include, but are not limited to, vaccinia, fowlpox, canarypox, adenovirus, influenza, poliovirus, adeno-associated virus, lentivirus, and Sindbis virus (Restifo, N. P., Curr. Opin. Immunol. (1996) 8:658-663). Non-viral delivery systems may also be employed by using naked DNA encoding a STEAP protein or fragment thereof introduced into the patient (e.g., intramuscularly) to induce an anti-tumor response. In one embodiment, the full-length human STEAP cDNA may be employed. In another embodiment, STEAP nucleic acid molecules encoding specific cytotoxic T lymphocyte (CTL) epitopes may be employed. CTL epitopes can be determined using specific algorithms (e.g., Epimer, Brown University) to identify peptides within a STEAP protein which are capable of optimally binding to specified HLA alleles. Optimally immunogenic HLA Class I molecule-binding peptides within the STEAP-1 and STEAP-2 sequences have been analyzed in Example 9, below.

[0141] Various ex vivo strategies may also be employed. One approach involves the use of dendritic cells to present STEAP antigen to a patient's immune system. Dendritic cells express MHC Class I and 11, B7 costimulator, and IL-12, and are thus highly specialized antigen presenting cells. In prostate cancer, autologous dendritic cells pulsed with peptides of the prostate-specific membrane antigen (PSMA) are being used in a Phase I clinical trial to stimulate prostate cancer patients' immune systems (Tjoa, B., et al., Prostate (1996) 28:65-69; Murphy, G., et al., Prostate (1996) 29:371-380). Dendritic cells can be used to present STEAP peptides to T cells in the context of MHC class I and II molecules. In one embodiment, autologous dendritic cells are pulsed with STEAP peptides capable of binding to MHC molecules. In another embodiment, dendritic cells are pulsed with the complete STEAP protein. Yet another embodiment involves engineering the overexpression of the STEAP gene in dendritic cells using various implementing vectors known in the art, such as adenovirus (Arthur, et al., Cancer Gene Ther. (1997) 4:17-25), retrovirus (Henderson, et al., Cancer Res. (1996) 56:3763-3770), lentivirus, adeno-associated virus, DNA transfection (Ribas, A., et al., Cancer Res. (1997) 57:2865-2869), and tumor-derived RNA transfection (Ashley, D. M., et al., J. Exp. Med. (1997) 186:1177-1182).

[0142] Anti-idiotypic anti-STEAP antibodies can also be used in anti-cancer therapy as a vaccine for inducing an immune response to cells expressing a STEAP protein. Specifically, the generation of anti-idiotypic antibodies is well known in the art and can readily be adapted to generate anti-idiotypic anti-STEAP antibodies that mimic an epitope on a STEAP protein (see, for example, Wagner, U., et al., Hybridoma (1997) 16:33-40; Foon, K. A., et al., J. Clin. Invest. (1995) 96:334-342; Herlyn, D., et al., Cancer Immunol. Immunother. (1996) 43:65-76). Such an anti-idiotypic antibody can be used in anti-idiotypic therapy as presently practiced with other anti-idiotypic antibodies directed against tumor antigens.

[0143] Genetic immunization methods may be employed to generate prophylactic or therapeutic humoral and cellular immune responses directed against cancer cells expressing STEAP. Constructs comprising DNA encoding a STEAP protein/immunogen and appropriate regulatory sequences may be injected directly into muscle or skin of an individual, such that the cells of the muscle or skin take-up the construct and express the encoded STEAP protein/immunogen. Expression of the STEAP protein immunogen results in the generation of prophylactic or therapeutic humoral and cellular immunity against prostate cancer. Various prophylactic and therapeutic genetic immunization techniques known in the art may be used (for review, see information and references published at Internet address www.genweb.com).

[0144] Kits

[0145] For use in the diagnostic and therapeutic applications described or suggested above, kits are also provided by the invention. Such kits may comprise a carrier means being compartmentalized to receive in close confinement one or more container means such as vials, tubes, and the like, each of the container means comprising one of the separate elements to be used in the method. For example, one of the container means may comprise a probe which is or can be detectably labeled. Such probe may be an antibody or polynucleotide specific for a STEAP protein or a STEAP gene or message, respectively. Where the kit utilizes nucleic acid hybridization to detect the target nucleic acid, the kit may also have containers containing nucleotide(s) for amplification of the target nucleic acid sequence and/or a container comprising a reporter-means, such as a biotin-binding protein, such as avidin or streptavidin, bound to a reporter molecule, such as an enzymatic, florescent, or radionucleotide label.

EXAMPLES

[0146] Various aspects of the invention are further described and illustrated by way of the several examples which follow, none of which are intended to limit the scope of the invention.

Example 1 Isolation of cDNA Fragment of STEAP-1 Gene Materials and Methods Cell Lines and Human Tissues

[0147] All human cancer cell lines used in this study were obtained from the ATCC. All cell lines were maintained in DMEM with 10% fetal calf serum. PrEC (primary prostate epithelial cells) were obtained from Clonetics and were grown in PrEBM media supplemented with growth factors (Clonetics).

[0148] All human prostate cancer xenografts were originally provided by Charles Sawyers (UCLA) (Klein, et al., 1997). LAPC-4 AD and LAPC-9 AD xenografts were routinely passaged as small tissue chunks in recipient SCID males. LAPC-4 AI and LAPC-9 AI xenografts were derived as described previously (Klein, et al., 1997) and were passaged in castrated males or in female SCID mice. A benign prostatic hyperplasia tissue sample was patient-derived.

[0149] Human tissues for RNA and protein analyses were obtained from the Human Tissue Resource Center (HTRC) at the UCLA (Los Angeles, Calif.) and from QualTek, Inc. (Santa Barbara, Calif.).

[0150] RNA Isolation:

[0151] Tumor tissue and cell lines were homogenized in TRIzol® reagent (Life Technologies, Gibco-BRL) using 10 ml/g tissue or 10 ml/10⁸ cells to isolate total RNA. Poly A RNA was purified from total RNA using Qiagen's Oligotex mRNA Mini and Midi kits. Total and mRNA were quantified by spectrophotometric analysis (O.D. 260/280 nm) and analyzed by gel electrophoresis.

[0152] Oligonucleotides:

[0153] The following HPLC purified oligonucleotides were used. RSACDN (cDNA synthesis primer): 5′TTTTGTACAAGCTT₃₀3′ (SEQ ID NO: 22) Adaptor 1: 5′CTAATACGACTCACTATAGGGCTCGAGCGGCCGCCCGGGCAGGT3′ (SEQ ID NO: 23) 3′GGCCCGTCCA5′ (SEQ ID NO: 24) Adaptor 2: 5′GTAATACGACTCACTATAGGGCAGCGTGGTCGCGGCCGAGGT3′ (SEQ ID NO: 25) 3′CGGCTCCA5′ (SEQ ID NO: 26) PCR primer 1: 5′CTAATACGACTCACTATAGGGC3′ (SEQ ID NO: 27) Nested primer (NP)1: 5′TCGAGCGGCCGCCCGGGCAGGT3′ (SEQ ID NO: 28) Nested primer (NP)2: 5′AGCGTGGTCGCGGCCGAGGT3′ (SEQ ID NO: 29)

[0154] Suppression Subtractive Hybridization:

[0155] Suppression Subtractive Hybridization (SSH) was used to identify cDNA's corresponding to genes which may be up-regulated in androgen dependent prostate cancer compared to benign prostatic hyperplasia.

[0156] Double stranded cDNA's corresponding to the LAPC-4 AD xenograft (tester) and the BPH tissue (driver) were synthesized from 2 μg of poly(A)⁺ RNA isolated from xenograft and BPH tissue, as described above, using Clontech's PCR-Select cDNA Subtraction Kit and 1 ng of oligonucleotide RSACDN as primer. First- and second-strand synthesis were carried out as described in the Kit's user manual protocol (Clontech Protocol No. PT1117-1, Catalog No. K1804-1). The resulting cDNA was digested with Rsa I for 3 hrs. at 37° C. Digested cDNA was extracted with phenol/chloroform (1:1) and ethanol precipitated.

[0157] Driver cDNA (BPH) was generated by combining in a 4 to 1 ratio Rsa I digested BPH cDNA with digested cDNA from mouse liver, in order to ensure that murine genes were subtracted from the tester cDNA (LAPC-4 AD).

[0158] Tester cDNA (LAPC-4 AD) was generated by diluting 1 μl of Rsa I digested LAPC-4 AD cDNA (400 ng) in 5 μl of water. The diluted cDNA (2 μl, 160 ng) was then ligated to 2 μl of adaptor 1 and adaptor 2 (10 μM), in separate ligation reactions, in a total volume of 10 μl at 16° C. overnight, using 400 u of T4 DNA ligase (Clontech). Ligation was terminated with 1 μl of 0.2 M EDTA and heating at 72° C. for 5 min.

[0159] The first hybridization was performed by adding 1.5 μl (600 ng) of driver cDNA to each of two tubes containing 1.5 μl (20 ng) adaptor 1- and adaptor 2-ligated tester cDNA. In a final volume of 4 μl, the samples were overlaid with mineral oil, denatured in an MJ Research® thermal cycler at 98° C. for 1.5 minutes, and then were allowed to hybridize for 8 hrs at 68° C. The two hybridizations were then mixed together with an additional 1 μl of fresh denatured driver cDNA and were allowed to hybridize overnight at 68° C. The second hybridization was then diluted in 200 μl of 20 mM Hepes, pH 8.3, 50 mM NaCl, 0.2 mM EDTA, heated at 70° C. for 7 min. and stored at −20° C.

[0160] PCR Amplification, Cloning and Sequencing of Gene Fragments Generated from SSH:

[0161] To amplify gene fragments resulting from SSH reactions, two PCR amplifications were performed. In the primary PCR reaction 1 μl of the diluted final hybridization mix was added to 1 μl of PCR primer 1 (10 μM), 0.5 μl dNTP mix (10 μM), 2.5 μl 10× reaction buffer (Clontech) and 0.5 μl 50× Advantage cDNA polymerase Mix (Clontech) in a final volume of 25 μl. PCR 1 was conducted using the following conditions: 75° C. for 5 min., 94° C. for 25 sec., then 27 cycles of 94° C. for 10 sec, 66° C. for 30 sec, 72° C. for 1.5 min. Five separate primary PCR reactions were performed for each experiment. The products were pooled and diluted 1:10 with water. For the secondary PCR reaction, 1 μl from the pooled and diluted primary PCR reaction was added to the same reaction mix as used for PCR 1, except that primers NP1 and NP2 (10 μM) were used instead of PCR primer 1. PCR 2 was performed using 10-12 cycles of 94° C. for 10 sec, 68° C. for 30 sec, 72° C. for 1.5 minutes. The PCR products were analyzed using 2% agarose gel electrophoresis.

[0162] The PCR products were inserted into pCR2.1 using the T/A vector cloning kit (Invitrogen). Transformed E. coli were subjected to blue/white and ampicillin selection. White colonies were picked and arrayed into 96 well plates and were grown in liquid culture overnight. To identify inserts, PCR amplification was performed on 1 ml of bacterial culture using the conditions of PCR 1 and NP1 and NP2 as primers. PCR products were analyzed using 2% agarose gel electrophoresis.

[0163] Bacterial clones were stored in 20% glycerol in a 96 well format. Plasmid DNA was prepared, sequenced, and subjected to nucleic acid homology searches of the GenBank, dbEST, and NCI-CGAP databases.

[0164] RT-PCR Expression Analysis:

[0165] First strand cDNA's were generated from 1 μg of mRNA with oligo (dT)12-18 priming using the Gibco-BRL Superscript Preamplification system. The manufacturers protocol was used and included an incubation for 50 min at 42° C. with reverse transcriptase followed by RNase H treatment at 37° C. for 20 min. After completing the reaction, the volume was increased to 200 μl with water prior to normalization. First strand cDNA's from 16 different normal human tissues were obtained from Clontech.

[0166] Normalization of the first strand cDNA's from multiple tissues was performed by using the primers 5′atatcgccgcgctcgtcgtcgacaa3′ and 5′agccacacgcagctcattgtagaagg3′ to amplify β-actin. First strand cDNA (5 μl) was amplified in a total volume of 50 μl containing 0.4 μM primers, 0.2 μM each dNTP's, 1×PCR buffer (Clontech, 10 mM Tris-HCL, 1.5 mM MgCl₂, 50 mM KCl, pH 8.3) and 1× KlenTaq® DNA polymerase (Clontech). Five μl of the PCR reaction was removed at 18, 20, and 22 cycles and used for agarose gel electrophoresis. PCR was performed using an MJ Research® thermal cycler under the following conditions: initial denaturation was at 94° C. for 15 sec, followed by a 18, 20, and 22 cycles of 94° C. for 15, 65° C. for 2 min, 72° C. for 5 sec. A final extension at 72° C. was carried out for 2 min. After agarose gel electrophoresis, the band intensities of the 283 bp β-actin bands from multiple tissues were compared by visual inspection. Dilution factors for the first strand cDNA's were calculated to result in equal β-actin band intensities in all tissues after 22 cycles of PCR. Three rounds of normalization were required to achieve equal band intensities in all tissues after 22 cycles of PCR.

[0167] To determine expression levels of the 8P1D4 gene, 5 μl of normalized first strand cDNA was analyzed by PCR using 25, 30, and 35 cycles of amplification using the following primer pairs, which were designed with the assistance of (MIT; for details, see, the internet address<http://www.genome.wi.mit.edu): 5′ ACT TTG TTG ATG ACC AGG ATT GGA 3′ (SEQ ID NO: 14) 5′ CAG AAC TTC AGC ACA CAC AGG AAC 3′ (SEQ ID NO: 15)

[0168] Semi quantitative expression analysis was achieved by comparing the PCR products at cycle numbers that give light band intensities.

[0169] Results:

[0170] Several SSH experiments were conduced as described in the Materials and Methods, supra, and led to the isolation of numerous candidate gene fragment clones. All candidate clones were sequenced and subjected to homology analysis against all sequences in the major public gene and EST databases in order to provide information on the identity of the corresponding gene and to help guide the decision to analyze a particular gene for differential expression. In general, gene fragments which had no homology to any known sequence in any of the searched databases, and thus considered to represent novel genes, as well as gene fragments showing homology to previously sequenced expressed sequence tags (EST's), were subjected to differential expression analysis by RT-PCR and/or Northern analysis.

[0171] One of the cDNA clones, designated 8P1D4, was 436 bp in length and showed homology to an EST sequence in the NCI-CGAP tumor gene database. The full length cDNA encoding the 8P1D4 gene was subsequently isolated using this cDNA and re-named STEAP-1. The 8P1D4 cDNA nucleotide sequence corresponds to nucleotide residues 150 through 585 in the STEAP-1 cDNA sequence as shown in FIG. 1A. Another clone, designated 28P3E1, 561 bp in length showed homology to a number of EST sequences in the NCI-CGAP tumor gene database or in other databases. Part of the 28P3E1 sequence (356 bp) is identical to an EST derived from human fetal tissue. After the full length STEAP-1 cDNA was obtained and sequenced, it became apparent that this clone also corresponds to STEAP-1 (more specifically, to residues 622 through the 3′ end of the STEAP-1 nucleotide sequence as shown in FIG. 1A).

[0172] Differential expression analysis by RT-PCR using primers derived from the 8P1D4 cDNA clone showed that the 8P1D4 (STEAP-1) gene is expressed at approximately equal levels in normal prostate and the LAPC-4 and LAPC-9 xenografts (FIG. 2, panel A). Further RT-PCR expression analysis of first strand cDNA's from 16 normal tissues showed greatest levels of 8P1D4 expression in prostate. Substantially lower level expression in several other normal tissues (i.e., colon, ovary, small intestine, spleen and testis) was detectable only at 30 cycles of amplification in brain, pancreas, colon and small intestine (FIG. 2, panels B and C).

Example 2 Isolation of Full Length STEAP-1 Encoding cDNA

[0173] The 436 bp 8P1D4 gene fragment (Example 1) was used to isolate additional cDNA's encoding the 8P1D4/STEAP-1 gene. Briefly, a normal human prostate cDNA library (Clontech) was screened with a labeled probe generated from the 436 bp 8P1D4 cDNA. One of the positive clones, clone 10, is 1195 bp in length and encodes a 339 amino acid protein having nucleotide and encoded amino acid sequences bearing no significant homology to any known human genes or proteins (homology to a rat Kidney Injury Protein recently described in International Application WO 98/53071). The encoded protein contains at least 6 predicted transmembrane motifs implying a cell surface orientation (see FIG. 1A, predicted transmembrane motifs underlined). These structural features led to the designation “STEAP”, for “Six Transmembrane Epithelial Antigen of the Prostate”. Subsequent identification of additional STEAP proteins led to the re-designation of the 8P1D4 gene product as “STEAP-1”. The STEAP-1 cDNA and encoded amino acid sequences are shown in FIG. 1A and correspond to SEQ ID NOS: 1 and 2, respectively. STEAP-1 cDNA clone 10 has been deposited with the American Type Culture Collection (“ATCC”) (Manassas, Va.) as plasmid 8P1D4 clone 10.1 on Aug. 26, 1998 as ATCC Accession No. 98849. The STEAP-1 cDNA clone can be excised therefrom using EcoRI/XbaI double digest (EcoRI at the 5′ end, XbaI at the 3′ end).

Example 3 STEAP-1 Gene and Protein Expression Analysis

[0174] In order to begin to characterize the biological characteristics of STEAP-1, an extensive evaluation of STEAP-1 mRNA and STEAP-1 protein expression across a variety of human tissue specimens was undertaken. This evaluation included Northern blot, Western blot and immunohistochemical analysis of STEAP-1 expression in a large number of normal human tissues, human prostate cancer xenografts and cell lines, and various other human cancer cell lines.

Example 3A Northern Blot Analysis of STEAP-1 mRNA Expression in Normal Human Tissues

[0175] Initial analysis of STEAP-1 mRNA expression in normal human tissues was conducted by Northern blotting two multiple tissue blots obtained from Clontech (Palo Alto, Calif.), comprising a total of 16 different normal human tissues, using labeled STEAP-1 clone 10 as a probe. RNA samples were quantitatively normalized with a β-actin probe. The results are shown in FIG. 3A. The highest expression level was detected in normal prostate, with an approximately 5-10 fold lower level of expression detected in colon and liver. These northern blots showed two transcripts of approximately 1.4 kb and 4.0 kb, the former of which corresponds to the full length STEAP-1 clone 10 cDNA, which encodes the entire STEAP-1 open reading frame. The larger transcript was separately cloned as a 3627 bp cDNA from a normal prostate library, the sequence of which contains a 2399 bp intron (FIG. 4).

[0176] This initial analysis was extended by using the STEAP-1 clone 10 probe to analyze an RNA dot blot matrix of 37 normal human tissues (Clontech, Palo Alto, Calif.; Human Master Blot™). The results are shown in FIG. 3B and show strong STEAP-1 expression only in prostate. Very low level STEAP-1 RNA expression was detected in liver, lung, trachea and fetal liver tissue, at perhaps a 5-fold lower level compared to prostate. No expression was detected in any of the remaining tissues. Based on these analyses, significant STEAP-1 expression appears to be prostate specific in normal tissues.

Example 3B Northern Blot Analysis of STEAP-1 mRNA Expression in Prostate Cancer Xenografts and Cell Lines

[0177] To analyze STEAP-1 expression in human cancer tissues and cell lines, RNA's derived from human prostate cancer xenografts and an extensive panel of prostate and non-prostate cancer cell lines were analyzed by Northern blot using STEAP-1 cDNA clone 10 as probe. All RNA samples were quantitatively normalized by ethidium bromide staining and subsequent analysis with a labeled β-actin probe.

[0178] The results, presented in FIG. 5, show high level STEAP-1 expression in all the LAPC xenografts and all of the prostate cancer cell lines. Expression in the LAPC-9 xenografts was higher compared to the LAPC-4 xenografts, with no significant difference observed between androgen-dependent and androgen-independent sublines (FIG. 5A). Expression in the LAPC-4 xenografts was comparable to expression in normal prostate. Lower levels of expression were detected in PrEC cells (Clonetics), which represent the basal cell compartment of the prostate. Analysis of prostate cancer cell lines showed highest expression levels in LNCaP, an androgen dependent prostate carcinoma cell line. Significant expression was also detected in the androgen-independent cell lines PC-3 and DU145. High levels of STEAP expression were also detected in LAPC-4 and LAPC-9 tumors that were grown within the tibia of mice as a model of prostate cancer bone metastasis (FIG. 5B).

[0179] Significantly, very strong STEAP-1 expression was also detected in many of the non-prostate human cancer cell lines analyzed (FIG. 5A). Particularly high level expression was observed in RD-ES cells, an Ewing sarcoma (EWS) derived cell line. Additionally, very high level expression was also detected in several of the colon cancer cell lines (e.g., CaCo-2, LoVo, T84 and Colo-205), bladder carcinoma cell lines (e.g., SCABER, UM-UC-3, TCCSUP and 5637), ovarian cancer cell lines (e.g., OV-1063 and SW 626) and pancreatic cancer cell lines (e.g., HPAC, Capan-1, PANC-1 and BxPC-3). These results, combined with the absence of strong expression in the corresponding normal tissues (FIG. 3), indicate that STEAP-1 may be generally up-regulated in these types (as well as other types) of human cancers.

Example 3C Western Blot Analysis of STEAP-1 Protein Expression in Prostate and Other Cancers

[0180] A 15 mer peptide corresponding to amino acid residues 14 through 28 of the STEAP-1 amino acid sequence as shown in FIG. 1A (WKMKPRRNLEEDDYL) (SEQ ID NO: 35) was synthesized and used to immunize sheep for the generation of sheep polyclonal antibodies towards the amino-terminus of the protein (anti-STEAP-1) as follows. The peptide was conjugated to KLH (keyhole limpet hemocyanin). The sheep was initially immunized with 400 μg of peptide in complete Freund's adjuvant. The animal was subsequently boosted every two weeks with 200 μg of peptide in incomplete Freund's adjuvant. Anti-STEAP antibody was affinity-purified from sheep serum using STEAP peptide coupled to Affi-Gel 10 (Bio-Rad). Purified antibody is stored in phosphate-buffered saline with 0.1% sodium azide.

[0181] To test antibody specificity, the cDNA of STEAP-1 was cloned into a retroviral expression vector (pSRαtkneo, Muller, A. J., et al., Mol. Cell. Biol. (1991) 11:1785-1792). National Institutes of Health (NIH) 3T3 cells were infected with retroviruses encoding STEAP-1 and were selected in G418 for 2 weeks. Western blot analysis of protein extracts of infected and un-infected NIH 3T3 cells showed expression of a protein with an apparent molecular weight of 36 kD only in the infected cells (FIG. 6, lanes marked “3T3 STEAP” AND “3T3”).

[0182] The anti-STEAP-1 polyclonal antibody was used to probe Western blots of cell lysates prepared from a variety of prostate cancer xenograft tissues, prostate cancer cell lines and other non-prostate cancer cell lines. Protein samples (20 μg each) were quantitatively normalized by probing the blots with an anti-Grb-2 antibody.

[0183] The results are shown in FIG. 6. STEAP-1 protein was detected in all of the LAPC prostate cancer xenografts, all of the prostate cancer cell lines, a primary prostate cancer specimen and its matched normal prostate control. Highest STEAP-1 protein expression was detected in the LAPC-9 xenograft and in LNCaP cells, in agreement with the Northern blot analysis described immediately above. High level expression was also observed in the bladder carcinoma cell line UM-UC-3. Expression in other cancer cell lines was also detectable (FIG. 6).

Example 3D Immunohistochemical Analysis of STEAP-1 Protein Expression in Prostate Tumor Biopsy and Surgical Specimens

[0184] To determine the extent of STEAP-1 protein expression in clinical materials, tissue sections were prepared from a variety of prostate cancer biopsies and surgical samples for immunohistochemical analysis. Tissues were fixed in 10% formalin, embedded in paraffin, and sectioned according to standard protocol. Formalin-fixed, paraffin-embedded sections of LNCaP cells were used as a positive control. Sections were stained with an anti-STEAP-1 polyclonal antibody directed against a STEAP-1 N-terminal epitope (as described immediately above). LNCaP sections were stained in the presence of an excess amount of the STEAP-1 N-terminal peptide immunogen used to generate the polyclonal antibody (peptide 1) or a non-specific peptide derived from a distinct region of the STEAP-1 protein (peptide 2; YQQVQQNKEDAWIEH) (SEQ ID NO: 30).

[0185] The results are shown in FIG. 8. LNCaP cells showed uniformly strong peri-cellular staining in all cells (FIG. 8b). Excess STEAP N-terminal peptide (peptide 1) was able to competitively inhibit antibody staining (FIG. 8a), while peptide 2 had no effect (FIG. 8b). Similarly, uniformly strong peri-cellular staining was seen in the LAPC-9 (FIG. 8f) and LAPC-4 prostate cancer xenografts (data not shown). These results are clear and suggest that the staining is STEAP specific. Moreover, these results visually localize STEAP to the plasma membrane, corroborating the biochemical findings presented in Example 4 below.

[0186] The results obtained with the various clinical specimens are show in FIG. 8c (normal prostate tissue), FIG. 8d (grade 3 prostatic carcinoma), and FIG. 8e (grade 4 prostatic carcinoma), and are also included in the summarized results shown in Table 1. Light to strong staining was observed in the glandular epithelia of all prostate cancer samples tested as well as in all samples derived from normal prostate or benign disease. The signal appears to be strongest at the cell membrane of the epithelial cells, especially at the cell-cell junctions (FIGS. 8c, d and e) and is also inhibited with excess STEAP N-terminal peptide 1 (data not shown). Some basal cell staining is also seen in normal prostate (FIG. 8c), which is more apparent when examining atrophic glands (data not shown). STEAP-1 seems to be expressed at all stages of prostate cancer since lower grades (FIG. 8d), higher grades (FIG. 8e) and metastatic prostate cancer (represented by LAPC-9; FIG. 8f) all exhibit strong staining.

[0187] Immunohistochemical staining of a large panel of normal non-prostate tissues showed no detectable STEAP-1 expression in 24 of 27 of these normal tissues (Table 1). Only three tissue samples showed some degree of anti-STEAP-1 staining. In particular, normal bladder exhibited low levels of cell surface staining in the transitional epithelium (FIG. 8g). Pancreas and pituitary showed low levels of cytoplasmic staining (Table 1). It is unclear whether the observed cytoplasmic staining is specific or is due to non-specific binding of the antibody, since northern blotting showed little to no STEAP-1 expression in pancreas (FIG. 3). Normal colon, which exhibited higher mRNA levels than pancreas by Northern blotting (FIG. 3), exhibited no detectable staining with anti-STEAP antibodies (FIG. 8h). These results indicate that cell surface expression of STEAP-1 in normal tissues appears to be restricted to prostate and bladder. TABLE 1 Immunohistochemical Staining of Human Tissues With Anti-STEAP-1 Polyclonal Antibody STAINING INTENSITY TISSUE NONE cerebellum, cerebral cortex, spinal cord, heart, skeletal muscle, artery, thymus, spleen, bone marrow, lymph node, lung, colon, liver, stomach, kidney, testis, ovary, fallopian tubes, placenta, uterus, breast, adrenal gland, thyroid gland, skin, bladder (3/5) LIGHT TO bladder (2/5), pituitary gland (cytoplasmic), pancreas MODERATE (cytoplasmic), BPH (3/5), prostate cancer (3/10) STRONG prostate (2/2), BPH (2/5), prostate cancer** (7/10)

Example 4 Biochemical Characterization of STEAP-1 Protein

[0188] To initially characterize the STEAP-1 protein, cDNA clone 10 was cloned into the pcDNA 3.1 Myc-His plasmid (Invitrogen), which encodes a 6-His tag at the carboxyl-terminus, transfected into 293T cells, and analyzed by flow cytometry using anti-His monoclonal antibody (His-probe, Santa Cruz) as well as the anti-STEAP-1 polyclonal antibody described above. Staining of cells was performed on intact cells as well as permeabilized cells. The results indicated that only permeabilized cells stained with both antibodies, suggesting that both termini of the STEAP-1 protein are localized intracellularly. It is therefore possible that one or more of the STEAP-1 protein termini are associated with intracellular organelles rather than the plasma membrane.

[0189] To determine whether STEAP-1 protein is expressed at the cell surface, intact STEAP-1-transfected 293T cells were labeled with a biotinylation reagent that does not enter live cells. STEAP-1 was then immunoprecipitated from cell extracts using the anti-His and anti-STEAP antibodies. SV40 large T antigen, an intracellular protein that is expressed at high levels in 293T cells, and the endogenous cell surface transferrin receptor were immunoprecipitated as negative and positive controls, respectively. After immunoprecipitation, the proteins were transferred to a membrane and visualized with horseradish peroxidase-conjugated streptavidin. The results of this analysis are shown in FIG. 7. Only the transferrin receptor (positive control) and STEAP-1 were labeled with biotin, while the SV40 large T antigen (negative control) was not detectably labeled (FIG. 7A). Since only cell surface proteins are labeled with this technique, it is clear from these results that STEAP-1 is a cell surface protein. Combined with the results obtained from the flow cytometric analysis, it is clear that STEAP-1 is a cell surface protein with intracellular amino- and carboxyl-termini.

[0190] Furthermore, the above results together with the STEAP-1 secondary structural predictions, shows that STEAP-1 is a type IIIa membrane protein with a molecular topology of six potential transmembrane domains, three extracellular loops, two intracellular loops and two intracellular termini. A schematic representation of STEAP-1 protein topology relative to the cell membrane is shown in FIG. 1B.

[0191] In addition, prostate, bladder and colon cancer cells were directly analyzed for cell surface expression of STEAP-1 by biotinylation studies. Briefly, biotinylated cell surface proteins were affinity purified with streptavidin-gel and probed with the anti-STEAP-1 polyclonal antibody described above. Western blotting of the streptavidin purified proteins clearly show cell surface biotinylation of endogenous STEAP-1 in all prostate (LNCaP, PC-3, DU145), bladder (UM-UC-3, TCCSUP) and colon cancer (LoVo, Colo) cells tested, as well as in NIH 3T3 cells infected with a STEAP-1 encoding retrovirus, but not in non-expressing NIH 3T3 cells used as a negative control (FIG. 7B). In a further negative control, STEAP-1 protein was not detected in streptavidin precipitates from non-biotinylated, STEAP expressing cells (FIG. 7B).

Example 5 Identification and Structural Analysis Other Human STEAP's

[0192] STEAP-1 has no homology to any known human genes. In an attempt to identify additional genes that are homologous to STEAP-1, the protein sequence of STEAP-1 was used as an electronic probe to identify family members in the public EST (expression sequence tag) database (dbEST). Using the “tblastn” function in NCBI (National Center for Biotechnology Information), the dbEST database was queried with the STEAP-1 protein sequence. This analysis revealed additional putative STEAP-1 homologues or STEAP family members, as further described below.

[0193] In addition, SSH cloning experiments also identified a STEAP-1 related cDNA fragment, clone 98P4B6. This clone was isolated from SSH cloning using normal prostate cDNA as tester and LAPC-4 AD cDNA as driver. A larger partial sequence of the 98P4B6 clone was subsequently isolated from a normal prostate library; this clone encodes an ORF of 173 amino acids with close homology to the primary structure of STEAP-1, and thus was designated STEAP-2. A full length STEAP-2 cDNA of 2454 bp was isolated from a prostate library. The STEAP-2 nucleotide and encoded ORF amino acid sequences are shown in FIG. 9. An amino acid alignment of the STEAP-1 and partial STEAP-2 primary structures is shown in FIGS. 11A and 11B. STEAP-1 and -2 share 61% identity over their 171 amino acid residue overlap (FIG. 11B). The STEAP-2 cDNA has been deposited with the American Type Culture Collection (“ATCC”) (Manassas, Va.) as plasmid 98P4B6-GTD3 as ATCC Accession No. PTA-311.

[0194] The STEAP-2 cDNA (98P4B6-GTD3) contains a 355 bp 5′UTR (untranslated region) that is 72% GC rich, suggesting that it contains translational regulatory elements. The cDNA encodes an open reading frame (ORF) of 454 amino acids (a.a.) with six potential transmembrane domains. This is in contrast to STRAP, which is 339 a.a. in length. Alignment with STRAP-1 demonstrates 54.9% identity over a 237 amino acid overlap. Interestingly, the locations of the six putative transmembrane domains in STRAP-2 coincide with the locations of the transmembrane domains in STRAP-1 (see alignment). The homology of STRAP-2 with STRAP-1 is highest in the regions spanned by the first putative extracellular loop to the fifth transmembrane domain. This analysis and the sequence of STRAP-2 suggest some significant differences between STRAP-1 and STRAP-2: STRAP-2 exhibits a 205 a.a. long intracellular N-terminus (compared to 69 a.a. in STRAP-1) and a short 4 a.a. intracellular C-terminus (compared to 26 a.a. in STRAP-1). These differences could imply significant differences in function and/or interaction with intracellular signaling pathways. To identify a unique mouse EST corresponding to STRAP-2, the unique N-terminus of STRAP-2 was used to query the dbEST database. One mouse EST was isolated (AI747886, mouse kidney) that may be used in the identification of mouse STRAP-2 and in expression analysis of STRAP-2 in mouse.

[0195] Two EST's encoding ORF's bearing close homology to the STEAP-1 and STEAP-2 sequences were also identified by electronic probing with the STEAP-1 protein sequence. These EST's (AI139607 and R80991) were provisionally designated STEAP-3 and STEAP-4. A full length cDNA encoding STEAP-3 was subsequently cloned, and its nucleotide and deduced amino acid sequences are shown in FIG. 10A. The nucleotide sequences of the EST's corresponding to the STEAP's are reproduced in FIG. 10B.

[0196] An amino acid alignment of the structures of STEAP-1, STEAP-2, STEAP-3 and the partial sequence of the putative STEAP-4 is shown in FIG. 11A. This alignment shows a close structural similarity between all four STEAP family proteins, particularly in the predicted transmembrane domains. As indicated above, STEAP-1 and STEAP-2 demonstrate 54.9% identity over a 237 amino acid overlap. STEAP-1 and STEAP-3 are 40.9% identical over a 264 amino acid region, while STEAP-2 and STEAP-3 are 47.8% identical over a 416 amino acid region.

Example 6 Expression Analysis of STEAP-2 and Other Human STEAP Family Members Example 6A Tissue Specific Expression of STEAP Family Members in Normal Human Tissues

[0197] RT-PCR analysis of STEAP-2 shows expression in all the LAPC prostate cancer xenografts and in normal prostate (FIG. 14, panel A). Analysis of 8 normal human tissues shows prostate-specific expression after 25 cycles of amplification (FIG. 14, panel B). Lower level expression in other tissues was detected only after 30 cycles of amplification. Northern blotting for STEAP-2 shows a pattern of 2 transcripts (approximately 3 and 8 kb in size) expressed only in prostate (and at significantly lower levels in the LAPC xenografts), with no detectable expression in any of the 15 other normal human tissues analyzed (FIG. 15, panel C). Thus, STEAP-2 expression in normal human tissues appears to be highly prostate-specific.

[0198] Expression analysis of STEAP family members in normal tissues was performed by Northern blot and/or RT-PCR. All STEAP family members appeared to exhibit tissue restricted expression patterns. STEAP-3/AI139607 expression is shown in FIG. 12A (Northern) and FIG. 12B (RT-PCR). STEAP-4/R80991 expression is shown in FIG. 13.

Example 6B Expression of STEAP-2 in Various Cancer Cell Lines

[0199] The RT-PCR results above suggested that the different STEAP family members exhibit different tissue expression patterns. Interestingly, STEAP-2, which appears very prostate-specific, seems to be expressed at lower levels in the LAPC xenografts. This is in contrast to STEAP-1, which is highly expressed in both normal and malignant prostate tissue.

[0200] To better characterize this suggested difference in the STEAP-2 prostate cancer expression profile (relative to STEAP-1), Northern blotting was performed on RNA derived from the LAPC xenografts, as well as several prostate and other cancer cell lines, using a STEAP-2 specific probe (labeled cDNA clone 98P4B6). The results are shown in FIG. 16 and can be summarized as follows. STEAP-2 is highly expressed in normal prostate and in some of the prostate cancer xenografts and cell lines. More particularly, very strong expression was observed in the LAPC-9 AD xenograft and the LNCaP cells. Significantly attenuated or no expression was observed in the other prostate cancer xenografts and cell lines. Very strong expression was also evident in the Ewing sarcoma cell line RD-ES. Unlike STEAP-1, which is highly expressed in cancer cell lines derived from bladder, colon, pancreatic and ovarian tumors, STEAP-2 showed low to non-detectable expression in these same cell lines (compare with FIG. 5). Interestingly, STEAP-2 was also non-detectable in PrEC cells, which are representative of the normal basal cell compartment of the prostate. These results suggest that expression of STEAP-1 and STEAP-2 are differentially regulated. While STEAP-1 may be a gene that is generally up-regulated in cancer, STEAP-2 may be a gene that is more restricted to normal prostate and prostate cancer.

Example 7 Chromosomal Localization of STEAP Genes

[0201] The chromosomal localization of STEAP-1 was determined using the GeneBridge 4 Human/Hamster radiation hybrid (RH) panel (Walter, M. A., et al., Nat. Genet. (1994) 7:22-28) (Research Genetics, Huntsville Ala.), while STEAP-2 and the STEAP homologues were mapped using the Stanford G3 radiation hybrid panel (Stewart, E., et al., Genome Res. (1997) 7:422-433).

[0202] The following PCR primers were used for STEAP-1: 8P1D4.1 5′ ACTTTGTTGATGACCAGGATTGGA 3′ (SEQ ID NO: 36) 8P1D4.2 5′ CAGAACTTCAGCACACACAGGAAC 3′ (SEQ ID NO: 37)

[0203] The resulting STEAP-1 mapping vector for the 93 radiation hybrid panel DNA's (2100000201101010001000000101110101221000111001110110101000100010001010010 21000001111001010000), and the mapping program available at the internet address <http://www-genome.wi.mit.edu/cgi-bin/contig/rhmapper.p1>, localized the STEAP-1 gene to chromosome 7p22.3, telomeric to D7S531.

[0204] The following PCR primers were used for 98P4B6/STEAP-2: 98P4B6.1 5′ GACTGAGCTGGAACTGGAATTTGT 3′ (SEQ ID NO: 31) 98P4B6.2 5′ TTTGAGGAGACTTCATCTCACTGG 3′ (SEQ ID NO: 32)

[0205] The resulting vector (0000010010000000000000000000000010010000000000 1000100000000000001000010101010010011), and the mapping program available at the internet address<http://www-shgc.stanford.edu/RH/rhserverformew.html>maps the 98P4B6 (STEAP-2) gene to chromosome 7q21.

[0206] The following PCR primers were used for AI139607: AI139607.1 5′ TTAGGACAACTTGATCACCAGCA 3′ (SEQ ID NO: 16) AI139607.2 5′ TGTCCAGTCCAAACTGGGTTATTT 3′ (SEQ ID NO: 17)

[0207] The resulting vector (00000000100000000000000000001000100000200000001000 100000001000000100010001010000010), and the mapping program available at the internet address <http://www-shgc.stanford.edu/RH/rhserverformew.html>, maps AI139607 to chromosome 7q21.

[0208] The following PCR primers were used for R80991: R80991.3 5′ ACAAGAGCCACCTCTGGGTGAA 3′ (SEQ ID NO: 33) R80991.4 5′ AGTTGAGCGAGTTTGCAATGGAC 3′ (SEQ ID NO: 34)

[0209] The resulting vector (0000000000020000102000000001000000000000000000 0010000000001000011100000001001000001), and the mapping program available at the internet address <http://www-shgc.stanford.edu/RH/rhserverformew.html>maps R80991 to chromosome 2q14-q21, near D2S2591.

[0210] In summary, the above results show that three of the putative human STEAP family members localize to chromosome 7, as is schematically depicted in FIG. 17. In particular, the STEAP-1 gene localizes to the far telomeric region of the short arm of chromosome 7, at 7p22.3, while STEAP-2 and AI139607 localize to the long arm of chromosome 7, at 7q21 (FIG. 17). R80991 maps to chromosome 2q14-q21.

Example 8 Identification of Intron-Exon Boundaries of STEAP-1

[0211] Genomic clones for STEAP-1 were identified by searching GenBank for BAC clones containing STEAP-1 sequences, resulting in the identification of accession numbers AC004969 (PAC DJ1121E10) and AC005053 (BAC RG041D11). Using the sequences derived from the PAC and BAC clones for STEAP the intron-exon boundaries were defined (FIG. 18). A total of 4 exons and 3 introns were identified within the coding region of the STEAP gene. Knowledge of the exact exon-intron structure of the STEAP-1 gene may be used for designing primers within intronic sequences which in turn may be used for genomic amplification of exons. Such amplification permits single-stranded conformational polymorphism (SSCP) analysis to search for polymorphisms associated with cancer. Mutant or polymorphic exons may be sequenced and compared to wild type STEAP. Such analysis may be useful to identify patients who are more susceptible to aggressive prostate cancer, as well as other types of cancer, particularly colon, bladder, pancreatic, ovarian, cervical and testicular cancers.

[0212] Southern blot analysis shows that the STEAP-1 gene exists in several species including mouse (FIG. 19). Therefore, a mouse BAC library (Mouse ES 129-V release I, Genome Systems, FRAC-4431) was screened with the human cDNA for STEAP-1 (clone 10, Example 2). One positive clone, 12P11, was identified and confirmed by southern blotting (FIG. 20). The intron-exon boundary information for human STEAP may be used to identify the mouse STEAP-1 coding sequences.

[0213] The mouse STEAP-1 genomic clone may be used to study the biological role of STEAP-1 during development and tumorigenesis. Specifically, the mouse genomic STEAP-1 clone may be inserted into a gene knock-out (K/O) vector for targeted disruption of the gene in mice, using methods generally known in the art. In addition, the role of STEAP in metabolic processes and epithelial cell function may be elucidated. Such K/O mice may be crossed with other prostate cancer mouse models, such as the TRAMP model (Greenberg, N. M., et al., Proc. Natl. Acad. Sci. USA (1995) 92:3439), to determine whether STEAP influences the development and progression of more or less aggressive and metastatic prostate cancers.

Example 9 Prediction of HLA-A2 Binding Peptides from STEAP-1 and STEAP-2

[0214] The complete amino acid sequences of the STEAP-1 and STEAP-2 proteins were entered into the HLA Peptide Motif Search algorithm found in the Bioinformatics and Molecular Analysis Section (BIMAS) Web site (http://bimas.dcrt.nih.gov/). The HLA Peptide Motif Search algorithm was developed by Dr. Ken Parker based on binding of specific peptide sequences in the groove of HLA Class I molecules and specifically HLA-A2 (Falk, et al., Nature (1991) 351:290-296; Hunt, et al., Science (1992) 255:1261-1263; Parker, et al., J. Immunol. (1992) 149:3580-3587; Parker, et al., J. Immunol. (1994) 152:163-175). This algorithm allows location and ranking of 8-mer, 9-mer, and 10-mer peptides from a complete protein sequence for predicted binding to HLA-A2 as well as other HLA Class I molecules. Most HLA-A2 binding peptides are 9-mers favorably containing a leucine (L) at position 2 and a valine (V) or leucine (L) at position 9.

[0215] The results of STEAP-1 and STEAP-2 predicted binding peptides are shown in Table 2 below. For both proteins the top 5 ranking candidates are shown along with their location, the amino acid sequence of each specific peptide, and an estimated binding score. The binding score corresponds to the estimated half-time of dissociation of complexes containing the peptide at 37° C. at pH 6.5. Peptides with the highest binding score (i.e., 10776.470 for STEAP-1 peptide 165; 1789.612 for STEAP-2 peptide 227) are predicted to be the most tightly bound to HLA Class I on the cell surface and thus represent the best immunogenic targets for T-cell recognition. Actual binding of peptides to HLA-A2 can be evaluated by stabilization of HLA-A2 expression on the antigen-processing defective cell line T2 (Refs. 5,6). Immunogenicity of specific peptides can be evaluated in vitro by stimulation of CD8+ cytotoxic T lymphocytes (CTL) in the presence of dendritic cells (Xue, B. H., et al., Prostate (1997) 30:73-78; Peshwa, M. V., et al., Prostate (1998) 36:129-138). TABLE 2 Predicted Binding of STEAP-1 and STEAP-2 Peptide Sequences with Highest Affinity for HLA-A2 Score (Estimate of Half Time of Start Disassociation of a Molecule Rank Position Subsequence Residue Listing containing This Subsequence STEAP-1 1 165 GLLSFFFAV (SEQ ID NO: 38) 10776.470 2  86 FLYTLLREV (SEQ ID NO: 39) 470.951 3 262 LLLGTIHAL (SEQ ID NO: 40) 309.050 4 302 LIFKSILFL (SEQ ID NO: 41) 233.719 5 158 MLTRKQFGL (SEQ ID NO: 42) 210.633 STEAP-2 1 227 FLYSFVRDV (SEQ ID NO: 43) 1789.612 2 402 ALLISTFHV (SEQ ID NO: 44) 1492.586 3 307 LLSFFFAMV (SEQ ID NO: 45) 853.681 4 306 GLLSFFFAM (SEQ ID NO: 46) 769.748 5 100 SLWDLRHLL (SEQ ID NO: 47) 726.962

[0216] This application is a continuation-in-part of U.S. application Ser. No. 09/323,873 filed Jun. 1, 1999, entitled “NOVEL SERPENTINE TRANSMEMBRANE ANTIGENS EXPRESSED 1N HUMAN CANCERS AND USES THEREOF” The proteins designated “STRAP” in that application have been re-named “STEAP” in the present application.

[0217] Throughout this application, various publications are referenced within parentheses. The disclosures of these publications are hereby incorporated by reference herein in their entireties.

[0218] The present invention is not to be limited in scope by the embodiments disclosed herein, which are intended as single illustrations of individual aspects of the invention, and any which are functionally equivalent are within the scope of the invention. Various modifications to the models and methods of the invention, in addition to those described herein, will become apparent to those skilled in the art from the foregoing description and teachings, and are similarly intended to fall within the scope of the invention. Such modifications or other embodiments can be practiced without departing from the true scope and spirit of the invention.

1 47 1 1193 DNA Homo sapiens CDS (64)...(1083) 1 gagactcacg gtcaagctaa ggcgaagagt gggtggctga agccatacta ttttatagaa 60 tta atg gaa agc aga aaa gac atc aca aac caa gaa gaa ctt tgg aaa 108 Met Glu Ser Arg Lys Asp Ile Thr Asn Gln Glu Glu Leu Trp Lys 1 5 10 15 atg aag cct agg aga aat tta gaa gaa gac gat tat ttg cat aag gac 156 Met Lys Pro Arg Arg Asn Leu Glu Glu Asp Asp Tyr Leu His Lys Asp 20 25 30 acg gga gag acc agc atg cta aaa aga cct gtg ctt ttg cat ttg cac 204 Thr Gly Glu Thr Ser Met Leu Lys Arg Pro Val Leu Leu His Leu His 35 40 45 caa aca gcc cat gct gat gaa ttt gac tgc cct tca gaa ctt cag cac 252 Gln Thr Ala His Ala Asp Glu Phe Asp Cys Pro Ser Glu Leu Gln His 50 55 60 aca cag gaa ctc ttt cca cag tgg cac ttg cca att aaa ata gct gct 300 Thr Gln Glu Leu Phe Pro Gln Trp His Leu Pro Ile Lys Ile Ala Ala 65 70 75 att ata gca tct ctg act ttt ctt tac act ctt ctg agg gaa gta att 348 Ile Ile Ala Ser Leu Thr Phe Leu Tyr Thr Leu Leu Arg Glu Val Ile 80 85 90 95 cac cct tta gca act tcc cat caa caa tat ttt tat aaa att cca atc 396 His Pro Leu Ala Thr Ser His Gln Gln Tyr Phe Tyr Lys Ile Pro Ile 100 105 110 ctg gtc atc aac aaa gtc ttg cca atg gtt tcc atc act ctc ttg gca 444 Leu Val Ile Asn Lys Val Leu Pro Met Val Ser Ile Thr Leu Leu Ala 115 120 125 ttg gtt tac ctg cca ggt gtg ata gca gca att gtc caa ctt cat aat 492 Leu Val Tyr Leu Pro Gly Val Ile Ala Ala Ile Val Gln Leu His Asn 130 135 140 gga acc aag tat aag aag ttt cca cat tgg ttg gat aag tgg atg tta 540 Gly Thr Lys Tyr Lys Lys Phe Pro His Trp Leu Asp Lys Trp Met Leu 145 150 155 aca aga aag cag ttt ggg ctt ctc agt ttc ttt ttt gct gta ctg cat 588 Thr Arg Lys Gln Phe Gly Leu Leu Ser Phe Phe Phe Ala Val Leu His 160 165 170 175 gca att tat agt ctg tct tac cca atg agg cga tcc tac aga tac aag 636 Ala Ile Tyr Ser Leu Ser Tyr Pro Met Arg Arg Ser Tyr Arg Tyr Lys 180 185 190 ttg cta aac tgg gca tat caa cag gtc caa caa aat aaa gaa gat gcc 684 Leu Leu Asn Trp Ala Tyr Gln Gln Val Gln Gln Asn Lys Glu Asp Ala 195 200 205 tgg att gag cat gat gtt tgg aga atg gag att tat gtg tct ctg gga 732 Trp Ile Glu His Asp Val Trp Arg Met Glu Ile Tyr Val Ser Leu Gly 210 215 220 att gtg gga ttg gca ata ctg gct ctg ttg gct gtg aca tct att cca 780 Ile Val Gly Leu Ala Ile Leu Ala Leu Leu Ala Val Thr Ser Ile Pro 225 230 235 tct gtg agt gac tct ttg aca tgg aga gaa ttt cac tat att cag agc 828 Ser Val Ser Asp Ser Leu Thr Trp Arg Glu Phe His Tyr Ile Gln Ser 240 245 250 255 aag cta gga att gtt tcc ctt cta ctg ggc aca ata cac gca ttg att 876 Lys Leu Gly Ile Val Ser Leu Leu Leu Gly Thr Ile His Ala Leu Ile 260 265 270 ttt gcc tgg aat aag tgg ata gat ata aaa caa ttt gta tgg tat aca 924 Phe Ala Trp Asn Lys Trp Ile Asp Ile Lys Gln Phe Val Trp Tyr Thr 275 280 285 cct cca act ttt atg ata gct gtt ttc ctt cca att gtt gtc ctg ata 972 Pro Pro Thr Phe Met Ile Ala Val Phe Leu Pro Ile Val Val Leu Ile 290 295 300 ttt aaa agc ata cta ttc ctg cca tgc ttg agg aag aag ata ctg aag 1020 Phe Lys Ser Ile Leu Phe Leu Pro Cys Leu Arg Lys Lys Ile Leu Lys 305 310 315 att aga cat ggt tgg gaa gac gtc acc aaa att aac aaa act gag ata 1068 Ile Arg His Gly Trp Glu Asp Val Thr Lys Ile Asn Lys Thr Glu Ile 320 325 330 335 tgt tcc cag ttg tag aattactgtt tacacacatt tttgttcaat attgatatat 1123 Cys Ser Gln Leu * tttatcacca acatttcaag tttgtatttg ttaataaaat gattattcaa ggaaaaaaaa 1183 aaaaaaaaaa 1193 2 339 PRT Homo sapiens 2 Met Glu Ser Arg Lys Asp Ile Thr Asn Gln Glu Glu Leu Trp Lys Met 1 5 10 15 Lys Pro Arg Arg Asn Leu Glu Glu Asp Asp Tyr Leu His Lys Asp Thr 20 25 30 Gly Glu Thr Ser Met Leu Lys Arg Pro Val Leu Leu His Leu His Gln 35 40 45 Thr Ala His Ala Asp Glu Phe Asp Cys Pro Ser Glu Leu Gln His Thr 50 55 60 Gln Glu Leu Phe Pro Gln Trp His Leu Pro Ile Lys Ile Ala Ala Ile 65 70 75 80 Ile Ala Ser Leu Thr Phe Leu Tyr Thr Leu Leu Arg Glu Val Ile His 85 90 95 Pro Leu Ala Thr Ser His Gln Gln Tyr Phe Tyr Lys Ile Pro Ile Leu 100 105 110 Val Ile Asn Lys Val Leu Pro Met Val Ser Ile Thr Leu Leu Ala Leu 115 120 125 Val Tyr Leu Pro Gly Val Ile Ala Ala Ile Val Gln Leu His Asn Gly 130 135 140 Thr Lys Tyr Lys Lys Phe Pro His Trp Leu Asp Lys Trp Met Leu Thr 145 150 155 160 Arg Lys Gln Phe Gly Leu Leu Ser Phe Phe Phe Ala Val Leu His Ala 165 170 175 Ile Tyr Ser Leu Ser Tyr Pro Met Arg Arg Ser Tyr Arg Tyr Lys Leu 180 185 190 Leu Asn Trp Ala Tyr Gln Gln Val Gln Gln Asn Lys Glu Asp Ala Trp 195 200 205 Ile Glu His Asp Val Trp Arg Met Glu Ile Tyr Val Ser Leu Gly Ile 210 215 220 Val Gly Leu Ala Ile Leu Ala Leu Leu Ala Val Thr Ser Ile Pro Ser 225 230 235 240 Val Ser Asp Ser Leu Thr Trp Arg Glu Phe His Tyr Ile Gln Ser Lys 245 250 255 Leu Gly Ile Val Ser Leu Leu Leu Gly Thr Ile His Ala Leu Ile Phe 260 265 270 Ala Trp Asn Lys Trp Ile Asp Ile Lys Gln Phe Val Trp Tyr Thr Pro 275 280 285 Pro Thr Phe Met Ile Ala Val Phe Leu Pro Ile Val Val Leu Ile Phe 290 295 300 Lys Ser Ile Leu Phe Leu Pro Cys Leu Arg Lys Lys Ile Leu Lys Ile 305 310 315 320 Arg His Gly Trp Glu Asp Val Thr Lys Ile Asn Lys Thr Glu Ile Cys 325 330 335 Ser Gln Leu 3 111 DNA Homo sapiens 3 ggcggaggcg gaggcggagg gcgaggggcg gggagcgccg cctggagcgc ggcaggtcat 60 attgaacatt ccagatacct atcattactc gatgctgttg ataacagcaa g 111 4 3627 DNA Homo sapiens 4 ggggcccgca cctctgggca gcagcggcag ccgagactca cggtcaagct aaggcgaaga 60 gtgggtggct gaagccatac tattttatag aattaatgga aagcagaaaa gacatcacaa 120 accaagaaga actttggaaa atgaagccta ggagaaattt agaagaagac gattatttgc 180 ataaggacac gggagagacc agcatgctaa aaagacctgt gcttttgcat ttgcaccaaa 240 cagcccatgc tgatgaattt gactgccctt cagaacttca gcacacacag gaactctttc 300 cacagtggca cttgccaatt aaaatagctg ctattatagc atctctgact tttctttaca 360 ctcttctgag ggaagtaatt caccccttag caacttccca tcaacaatat ttttataaaa 420 ttccaatcct ggtcatcaac aaagtcttgc caatggtttc catcactctc ttggcattgg 480 tttacctgcc aggtgtgata gcagcaattg tccaacttca taatggaacc aagtataaga 540 agtttccaca ttggttggat aagtggatgt taacaagaaa gcagtttggg cttctcagtt 600 tcttttttgc tgtactgcat gcaatttata gtctgtctta cccaatgagg cgatcctaca 660 gatacaagtt gctaaactgg gcatatcaac aggtccaaca aaataaagaa gatgcctgga 720 ttgagcatga tgtttggaga atggagattt atgtgtctct gggaattgtg ggattggcaa 780 tactggctct gttggctgtg acatctattc catctgtgag tgactctttg acatggagag 840 aatttcacta tattcaggta aataatatat aaaataaccc taagaggtaa atcttctttt 900 tgtgtttatg atatagaata tgttgacttt accccataaa aaataacaaa tgtttttcaa 960 cagcaaagat cttatacttg ttccaattaa taatgtgctc tcctgttgtt ttccctattg 1020 cttctaatta ggacaagtgt ttcctagaca taaataaaag gcattaaaat attctttgtt 1080 tttttttttt tgtttgtttg ttttttgttt gtttgtttgt ttttttgaga tgaagtctcg 1140 ctctgttgcc catgctggag tacagtggca cgatctcggc tcactgcaac ctgcgcctcc 1200 tgggttcagg cgattctctt gcctcagcct cctgagtagc tgggattaca ggcacccatc 1260 accatgtcca gctaattttt gtatttttag tagagacagg gttttcccat gttggccagg 1320 ctggtctcga tctcctgacc tcaaatgatc cgcccacctc ggcctcccaa agtgctggga 1380 tgacagttgt gagccaccac actcagcctg ctctttctaa tatttgaaac ttgttagaca 1440 atttgctacc catctaatgt gatattttag gaatccaata tgcatggttt attatttctt 1500 aaaaaaaata ttcttttacc tgtcacctga atttagtaat gccttttatg ttacacaact 1560 tagcactttc cagaaacaaa aactctctcc ttgaaataat agagttttta tctaccaaag 1620 atatgctagt gtctcatttc aaaggctgct ttttccagct tacattttat atacttactc 1680 acttgaagtt tctaaatatt cttgtaattt taaaactatc tcagatttac tgaggtttat 1740 cttctggtgg tagattatcc ataagaagag tgatgtgcca gaatcactct gggatccttg 1800 tctgacaaga ttcaaaggac taaatttaat tcagtcatga acactgccaa ttaccgttta 1860 tgggtagaca tctttggaaa tttccacaag gtcagacatt cgcaactatc ccttctacat 1920 gtccacacgt atactccaac actttattag gcatctgatt agtttggaaa gtatgcctcc 1980 atctgaatta gtccagtgtg gcttagagtt ggtacaacat tctcacagaa tttcctaatt 2040 ttgtaggttc agcctgataa ccactggagt tctttggtcc tcattaaata gctttcttca 2100 cacattgctc tgcctgttac acatatgatg aacactgctt tttagacttc attaggaatt 2160 taggactgca tcttgacaac tgagcctatt ctactatatg tacaatacct agcccataat 2220 aggtatacaa tacacatttg gtaaaactaa ttttcaacca atgacatgta tttttcaact 2280 agtaacctag aaatgtttca cttaaaatct gagaactggt tacactacaa gttaccttgg 2340 agattcatat atgaaaacgc aaacttagct atttgattgt attcactggg acttaagaat 2400 gcgcctgaat aattgtgagt tcgatttgtt ctggcaggct aatgaccatt tccagtaaag 2460 tgaatagagg tcagaagtcg tataaaagag gtgttgtcag aacaccgttg agattacata 2520 ggtgaacaac tatttttaag caactttatt tgtgtagtga caaagcatcc caatgcaggc 2580 tgaaatgttt catcacatct ctggatctct ctattttgtg cagacattga aaaaattgtt 2640 catattattt ccatgttatc agaatatttg attttttaaa aacataggcc aagttcattc 2700 acttcattat tcatttatca aaatcagagt gaatcacatt agtcgccttc acaactgata 2760 aagatcactg aagtcaaatt gatttttgct ataatcttca atctacctat atttaattga 2820 gaatctaaaa tgtacaaatc attgtgttga ttctgcagtg atcctgctat aagtaagact 2880 cagtccctga ttttaggtat cctgtgaaaa gcagaattaa gacaaataca caagagacaa 2940 agcacaaaaa ataaatatca taaggggatg aacaaaatgg tggagaaaga gtagacaaag 3000 tttttgatca cctgccttca aagaaaggct gtgaattttg ttcacttaga cagcttggag 3060 acaagaaatt acccaaaagt aaggtgagga ggataggcaa aaagagcaga aagatgtgaa 3120 tggacattgt tgagaaatgt gataggaaaa caatcataga taaaggattt ccaagcaaca 3180 gagcatatcc agatgaggta ggatgggata aactcttatt gaaccaatct tcaccaattt 3240 tgtttttctt ttgcagagca agctaggaat tgtttccctt ctactgggca caatacacgc 3300 attgattttt gcctggaata agtggataga tataaaacaa tttgtatggt atacacctcc 3360 aacttttatg atagctgttt tccttccaat tgttgtcctg atatttaaaa gcatactatt 3420 cctgccatgc ttgaggaaga agatactgaa gattagacat ggttgggaag acgtcaccaa 3480 aattaacaaa actgagatat gttcccagtt gtagaattac tgtttacaca catttttgtt 3540 caatattgat atattttatc accaacattt caagtttgta tttgttaata aaatgattat 3600 tcaaggaaaa aaaaaaaaaa aaaaaaa 3627 5 2453 DNA Homo sapiens CDS (355)...(1719) 5 ggacgcgtgg gcggacgcgt gggttcctcg ggccctcggc gccacaagct gtccgggcac 60 gcagccccta gcggcgcgtc gctgccaagc cggcctccgc gcgcctccct ccttccttct 120 cccctggctg ttcgcgatcc agcttgggta ggcggggaag cagctggagt gcgaccgcca 180 cggcagccac cctgcaaccg ccagtcggag gtgcagtccg taggccctgg cccccgggtg 240 ggcccttggg gagtcggcgc cgctcccgag gagctgcaag gctcgcccct gcccggcgtg 300 gagggcgcgg ggggcgcgga ggatattctt ggtgatcttg gaagtgtccg tatc atg 357 Met 1 gaa tca atc tct atg atg gga agc cct aag agc ctt agt gaa act tgt 405 Glu Ser Ile Ser Met Met Gly Ser Pro Lys Ser Leu Ser Glu Thr Cys 5 10 15 tta cct aat ggc ata aat ggt atc aaa gat gca agg aag gtc act gta 453 Leu Pro Asn Gly Ile Asn Gly Ile Lys Asp Ala Arg Lys Val Thr Val 20 25 30 ggt gtg att gga agt gga gat ttt gcc aaa tcc ttg acc att cga ctt 501 Gly Val Ile Gly Ser Gly Asp Phe Ala Lys Ser Leu Thr Ile Arg Leu 35 40 45 att aga tgc ggc tat cat gtg gtc ata gga agt aga aat cct aag ttt 549 Ile Arg Cys Gly Tyr His Val Val Ile Gly Ser Arg Asn Pro Lys Phe 50 55 60 65 gct tct gaa ttt ttt cct cat gtg gta gat gtc act cat cat gaa gat 597 Ala Ser Glu Phe Phe Pro His Val Val Asp Val Thr His His Glu Asp 70 75 80 gct ctc aca aaa aca aat ata ata ttt gtt gct ata cac aga gaa cat 645 Ala Leu Thr Lys Thr Asn Ile Ile Phe Val Ala Ile His Arg Glu His 85 90 95 tat acc tcc ctg tgg gac ctg aga cat ctg ctt gtg ggt aaa atc ctg 693 Tyr Thr Ser Leu Trp Asp Leu Arg His Leu Leu Val Gly Lys Ile Leu 100 105 110 att gat gtg agc aat aac atg agg ata aac cag tac cca gaa tcc aat 741 Ile Asp Val Ser Asn Asn Met Arg Ile Asn Gln Tyr Pro Glu Ser Asn 115 120 125 gct gaa tat ttg gct tca tta ttc cca gat tct ttg att gtc aaa gga 789 Ala Glu Tyr Leu Ala Ser Leu Phe Pro Asp Ser Leu Ile Val Lys Gly 130 135 140 145 ttt aat gtt gtc tca gct tgg gca ctt cag tta gga cct aag gat gcc 837 Phe Asn Val Val Ser Ala Trp Ala Leu Gln Leu Gly Pro Lys Asp Ala 150 155 160 agc cgg cag gtt tat ata tgc agc aac aat att caa gcg cga caa cag 885 Ser Arg Gln Val Tyr Ile Cys Ser Asn Asn Ile Gln Ala Arg Gln Gln 165 170 175 gtt att gaa ctt gcc cgc cag ttg aat ttc att ccc att gac ttg gga 933 Val Ile Glu Leu Ala Arg Gln Leu Asn Phe Ile Pro Ile Asp Leu Gly 180 185 190 tcc tta tca tca gcc aga gag att gaa aat tta ccc cta cga ctc ttt 981 Ser Leu Ser Ser Ala Arg Glu Ile Glu Asn Leu Pro Leu Arg Leu Phe 195 200 205 act ctc tgg aga ggg cca gtg gtg gta gct ata agc ttg gcc aca ttt 1029 Thr Leu Trp Arg Gly Pro Val Val Val Ala Ile Ser Leu Ala Thr Phe 210 215 220 225 ttt ttc ctt tat tcc ttt gtc aga gat gtg att cat cca tat gct aga 1077 Phe Phe Leu Tyr Ser Phe Val Arg Asp Val Ile His Pro Tyr Ala Arg 230 235 240 aac caa cag agt gac ttt tac aaa att cct ata gag att gtg aat aaa 1125 Asn Gln Gln Ser Asp Phe Tyr Lys Ile Pro Ile Glu Ile Val Asn Lys 245 250 255 acc tta cct ata gtt gcc att act ttg ctc tcc cta gta tac ctt gca 1173 Thr Leu Pro Ile Val Ala Ile Thr Leu Leu Ser Leu Val Tyr Leu Ala 260 265 270 ggt ctt ctg gca gct gct tat caa ctt tat tac ggc acc aag tat agg 1221 Gly Leu Leu Ala Ala Ala Tyr Gln Leu Tyr Tyr Gly Thr Lys Tyr Arg 275 280 285 aga ttt cca cct tgg ttg gaa acc tgg tta cag tgt aga aaa cag ctt 1269 Arg Phe Pro Pro Trp Leu Glu Thr Trp Leu Gln Cys Arg Lys Gln Leu 290 295 300 305 gga tta cta agt ttt ttc ttc gct atg gtc cat gtt gcc tac agc ctc 1317 Gly Leu Leu Ser Phe Phe Phe Ala Met Val His Val Ala Tyr Ser Leu 310 315 320 tgc tta ccg atg aga agg tca gag aga tat ttg ttt ctc aac atg gct 1365 Cys Leu Pro Met Arg Arg Ser Glu Arg Tyr Leu Phe Leu Asn Met Ala 325 330 335 tat cag cag gtt cat gca aat att gaa aac tct tgg aat gag gaa gaa 1413 Tyr Gln Gln Val His Ala Asn Ile Glu Asn Ser Trp Asn Glu Glu Glu 340 345 350 gtt tgg aga att gaa atg tat atc tcc ttt ggc ata atg agc ctt ggc 1461 Val Trp Arg Ile Glu Met Tyr Ile Ser Phe Gly Ile Met Ser Leu Gly 355 360 365 tta ctt tcc ctc ctg gca gtc act tct atc cct tca gtg agc aat gct 1509 Leu Leu Ser Leu Leu Ala Val Thr Ser Ile Pro Ser Val Ser Asn Ala 370 375 380 385 tta aac tgg aga gaa ttc agt ttt att cag tct aca ctt gga tat gtc 1557 Leu Asn Trp Arg Glu Phe Ser Phe Ile Gln Ser Thr Leu Gly Tyr Val 390 395 400 gct ctg ctc ata agt act ttc cat gtt tta att tat gga tgg aaa cga 1605 Ala Leu Leu Ile Ser Thr Phe His Val Leu Ile Tyr Gly Trp Lys Arg 405 410 415 gct ttt gag gaa gag tac tac aga ttt tat aca cca cca aac ttt gtt 1653 Ala Phe Glu Glu Glu Tyr Tyr Arg Phe Tyr Thr Pro Pro Asn Phe Val 420 425 430 ctt gct ctt gtt ttg ccc tca att gta att ctg gat ctt ttg cag ctt 1701 Leu Ala Leu Val Leu Pro Ser Ile Val Ile Leu Asp Leu Leu Gln Leu 435 440 445 tgc aga tac cca gac tga gctggaactg gaatttgtct tcctattgac 1749 Cys Arg Tyr Pro Asp * 450 tctacttctt taaaagcggc tgcccattac attcctcagc tgtccttgca gttaggtgta 1809 catgtgactg agtgttggcc agtgagatga agtctcctca aaggaaggca gcatgtgtcc 1869 tttttcatcc cttcatcttg ctgctgggat tgtggatata acaggagccc tggcagctgt 1929 ctccagagga tcaaagccac acccaaagag taaggcagat tagagaccag aaagaccttg 1989 actacttccc tacttccact gcttttcctg catttaagcc attgtaaatc tgggtgtgtt 2049 acatgaagtg aaaattaatt ctttctgccc ttcagttctt tatcctgata ccatttaaca 2109 ctgtctgaat taactagact gcaataattc tttcttttga aagcttttaa aggataatgt 2169 gcaattcaca ttaaaattga ttttccattg tcaattagtt atactcattt tcctgccttg 2229 atctttcatt agatattttg tatctgcttg gaatatatta tcttcttttt aactgtgtaa 2289 ttggtaatta ctaaaactct gtaatctcca aaatattgct atcaaattac acaccatgtt 2349 ttctatcatt ctcatagatc tgccttataa acatttaaat aaaaagtact atttaatgat 2409 ttaaaaaaaa aaaaaaaaaa aaaaaaaaaa aaaaaaaaaa aaaa 2453 6 454 PRT Homo sapiens 6 Met Glu Ser Ile Ser Met Met Gly Ser Pro Lys Ser Leu Ser Glu Thr 1 5 10 15 Cys Leu Pro Asn Gly Ile Asn Gly Ile Lys Asp Ala Arg Lys Val Thr 20 25 30 Val Gly Val Ile Gly Ser Gly Asp Phe Ala Lys Ser Leu Thr Ile Arg 35 40 45 Leu Ile Arg Cys Gly Tyr His Val Val Ile Gly Ser Arg Asn Pro Lys 50 55 60 Phe Ala Ser Glu Phe Phe Pro His Val Val Asp Val Thr His His Glu 65 70 75 80 Asp Ala Leu Thr Lys Thr Asn Ile Ile Phe Val Ala Ile His Arg Glu 85 90 95 His Tyr Thr Ser Leu Trp Asp Leu Arg His Leu Leu Val Gly Lys Ile 100 105 110 Leu Ile Asp Val Ser Asn Asn Met Arg Ile Asn Gln Tyr Pro Glu Ser 115 120 125 Asn Ala Glu Tyr Leu Ala Ser Leu Phe Pro Asp Ser Leu Ile Val Lys 130 135 140 Gly Phe Asn Val Val Ser Ala Trp Ala Leu Gln Leu Gly Pro Lys Asp 145 150 155 160 Ala Ser Arg Gln Val Tyr Ile Cys Ser Asn Asn Ile Gln Ala Arg Gln 165 170 175 Gln Val Ile Glu Leu Ala Arg Gln Leu Asn Phe Ile Pro Ile Asp Leu 180 185 190 Gly Ser Leu Ser Ser Ala Arg Glu Ile Glu Asn Leu Pro Leu Arg Leu 195 200 205 Phe Thr Leu Trp Arg Gly Pro Val Val Val Ala Ile Ser Leu Ala Thr 210 215 220 Phe Phe Phe Leu Tyr Ser Phe Val Arg Asp Val Ile His Pro Tyr Ala 225 230 235 240 Arg Asn Gln Gln Ser Asp Phe Tyr Lys Ile Pro Ile Glu Ile Val Asn 245 250 255 Lys Thr Leu Pro Ile Val Ala Ile Thr Leu Leu Ser Leu Val Tyr Leu 260 265 270 Ala Gly Leu Leu Ala Ala Ala Tyr Gln Leu Tyr Tyr Gly Thr Lys Tyr 275 280 285 Arg Arg Phe Pro Pro Trp Leu Glu Thr Trp Leu Gln Cys Arg Lys Gln 290 295 300 Leu Gly Leu Leu Ser Phe Phe Phe Ala Met Val His Val Ala Tyr Ser 305 310 315 320 Leu Cys Leu Pro Met Arg Arg Ser Glu Arg Tyr Leu Phe Leu Asn Met 325 330 335 Ala Tyr Gln Gln Val His Ala Asn Ile Glu Asn Ser Trp Asn Glu Glu 340 345 350 Glu Val Trp Arg Ile Glu Met Tyr Ile Ser Phe Gly Ile Met Ser Leu 355 360 365 Gly Leu Leu Ser Leu Leu Ala Val Thr Ser Ile Pro Ser Val Ser Asn 370 375 380 Ala Leu Asn Trp Arg Glu Phe Ser Phe Ile Gln Ser Thr Leu Gly Tyr 385 390 395 400 Val Ala Leu Leu Ile Ser Thr Phe His Val Leu Ile Tyr Gly Trp Lys 405 410 415 Arg Ala Phe Glu Glu Glu Tyr Tyr Arg Phe Tyr Thr Pro Pro Asn Phe 420 425 430 Val Leu Ala Leu Val Leu Pro Ser Ile Val Ile Leu Asp Leu Leu Gln 435 440 445 Leu Cys Arg Tyr Pro Asp 450 7 4429 DNA Homo sapiens CDS (85)...(1464) 7 cgaaacttcc ctctacccgc ccggcccgcg gcgcgcaccg ttggcgctgg acgcttcctc 60 cttggaagcg cctctccctc agtt atg gag aaa act tgt ata gat gca ctt 111 Met Glu Lys Thr Cys Ile Asp Ala Leu 1 5 cct ctt act atg aat tct tca gaa aag caa gag act gta tgt att ttt 159 Pro Leu Thr Met Asn Ser Ser Glu Lys Gln Glu Thr Val Cys Ile Phe 10 15 20 25 gga act ggt gat ttt gga aga tca ctg gga ttg aaa atg ctc cag tgt 207 Gly Thr Gly Asp Phe Gly Arg Ser Leu Gly Leu Lys Met Leu Gln Cys 30 35 40 ggt tat tct gtt gtt ttt gga agt cga aac ccc cag aag acc acc cta 255 Gly Tyr Ser Val Val Phe Gly Ser Arg Asn Pro Gln Lys Thr Thr Leu 45 50 55 ctg ccc agt ggt gca gaa gtc ttg agc tat tca gaa gca gcc aag aag 303 Leu Pro Ser Gly Ala Glu Val Leu Ser Tyr Ser Glu Ala Ala Lys Lys 60 65 70 tct ggc atc ata atc ata gca atc cac aga gag cat tat gat ttt ctc 351 Ser Gly Ile Ile Ile Ile Ala Ile His Arg Glu His Tyr Asp Phe Leu 75 80 85 aca gaa tta act gag gtt ctc aat gga aaa ata ttg gta gac atc agc 399 Thr Glu Leu Thr Glu Val Leu Asn Gly Lys Ile Leu Val Asp Ile Ser 90 95 100 105 aac aac ctc aaa atc aat caa tat cca gaa tct aat gca gag tac ctt 447 Asn Asn Leu Lys Ile Asn Gln Tyr Pro Glu Ser Asn Ala Glu Tyr Leu 110 115 120 gct cat ttg gtg cca gga gcc cac gtg gta aaa gca ttt aac acc atc 495 Ala His Leu Val Pro Gly Ala His Val Val Lys Ala Phe Asn Thr Ile 125 130 135 tca gcc tgg gct ctc cag tca gga gca ctg gat gca agt cgg cag gtg 543 Ser Ala Trp Ala Leu Gln Ser Gly Ala Leu Asp Ala Ser Arg Gln Val 140 145 150 ttt gtg tgt gga aat gac agc aaa gcc aag caa aga gtg atg gat att 591 Phe Val Cys Gly Asn Asp Ser Lys Ala Lys Gln Arg Val Met Asp Ile 155 160 165 gtt cgt aat ctt gga ctt act cca atg gat caa gga tca ctc atg gca 639 Val Arg Asn Leu Gly Leu Thr Pro Met Asp Gln Gly Ser Leu Met Ala 170 175 180 185 gcc aaa gaa att gaa aag tac ccc ctg cag cta ttt cca atg tgg agg 687 Ala Lys Glu Ile Glu Lys Tyr Pro Leu Gln Leu Phe Pro Met Trp Arg 190 195 200 ttc ccc ttc tat ttg tct gct gtg ctg tgt gtc ttc ttg ttt ttc tat 735 Phe Pro Phe Tyr Leu Ser Ala Val Leu Cys Val Phe Leu Phe Phe Tyr 205 210 215 tgt gtt ata aga gac gta atc tac cct tat gtt tat gaa aag aaa gat 783 Cys Val Ile Arg Asp Val Ile Tyr Pro Tyr Val Tyr Glu Lys Lys Asp 220 225 230 aat aca ttt cgt atg gct att tcc att cca aat cgt atc ttt cca ata 831 Asn Thr Phe Arg Met Ala Ile Ser Ile Pro Asn Arg Ile Phe Pro Ile 235 240 245 aca gca ctt aca ctg ctt gct ttg gtt tac ctc cct ggt gtt att gct 879 Thr Ala Leu Thr Leu Leu Ala Leu Val Tyr Leu Pro Gly Val Ile Ala 250 255 260 265 gcc att cta caa ctg tac cga ggc aca aaa tac cgt cga ttc cca gac 927 Ala Ile Leu Gln Leu Tyr Arg Gly Thr Lys Tyr Arg Arg Phe Pro Asp 270 275 280 tgg ctt gac cac tgg atg ctt tgc cga aag cag ctt ggc ttg gta gct 975 Trp Leu Asp His Trp Met Leu Cys Arg Lys Gln Leu Gly Leu Val Ala 285 290 295 ctg gga ttt gcc ttc ctt cat gtc ctc tac aca ctt gtg att cct att 1023 Leu Gly Phe Ala Phe Leu His Val Leu Tyr Thr Leu Val Ile Pro Ile 300 305 310 cga tat tat gta cga tgg aga ttg gga aac tta acc gtt acc cag gca 1071 Arg Tyr Tyr Val Arg Trp Arg Leu Gly Asn Leu Thr Val Thr Gln Ala 315 320 325 ata ctc aag aag gag aat cca ttt agc acc tcc tca gcc tgg ctc agt 1119 Ile Leu Lys Lys Glu Asn Pro Phe Ser Thr Ser Ser Ala Trp Leu Ser 330 335 340 345 gat tca tat gtg gct ttg gga ata ctt ggg ttt ttt ctg ttt gta ctc 1167 Asp Ser Tyr Val Ala Leu Gly Ile Leu Gly Phe Phe Leu Phe Val Leu 350 355 360 ttg gga atc act tct ttg cca tct gtt agc aat gca gtc aac tgg aga 1215 Leu Gly Ile Thr Ser Leu Pro Ser Val Ser Asn Ala Val Asn Trp Arg 365 370 375 gag ttc cga ttt gtc cag tcc aaa ctg ggt tat ttg acc ctg atc ttg 1263 Glu Phe Arg Phe Val Gln Ser Lys Leu Gly Tyr Leu Thr Leu Ile Leu 380 385 390 tgt aca gcc cac acc ctg gtg tac ggt ggg aag aga ttc ctc agc cct 1311 Cys Thr Ala His Thr Leu Val Tyr Gly Gly Lys Arg Phe Leu Ser Pro 395 400 405 tca aat ctc aga tgg tat ctt cct gca gcc tac gtg tta ggg ctt atc 1359 Ser Asn Leu Arg Trp Tyr Leu Pro Ala Ala Tyr Val Leu Gly Leu Ile 410 415 420 425 att cct tgc act gtg ctg gtg atc aag ttt gtc cta atc atg cca tgt 1407 Ile Pro Cys Thr Val Leu Val Ile Lys Phe Val Leu Ile Met Pro Cys 430 435 440 gta gac aac acc ctt aca agg atc cgc cag ggc tgg gaa agg aac tca 1455 Val Asp Asn Thr Leu Thr Arg Ile Arg Gln Gly Trp Glu Arg Asn Ser 445 450 455 aaa cac tag aaaaagcatt gaatggaaaa tcaatattta aaacaaagtt 1504 Lys His * caatttagct ggatttctga actatggttt tgaatgttta aagaagaatg atgggtacag 1564 ttaggaaagt ttttttctta caccgtgact gagggaaaca ttgcttgtct ttgagaaatt 1624 gactgacata ctggaagaga acaccatttt atctcaggtt agtgaagaat cagtgcaggt 1684 ccctgactct tattttccca gaggccatgg agctgagatt gagactagcc ttgtggtttc 1744 acactaaaga gtttccttgt tatgggcaac atgcatgacc taatgtcttg caaaatccaa 1804 tagaagtatt gcagcttcct tctctggctc aagggctgag ttaagtgaaa ggaaaaacag 1864 cacaatggtg accactgata aaggctttat taggtatatc tgaggaagtg ggtcacatga 1924 aatgtaaaaa gggaatgagg tttttgttgt tttttggaag taaaggcaaa cataaatatt 1984 accatgatga attctagtga aatgacccct tgactttgct tttcttaata cagatattta 2044 ctgagaggaa ctatttttat aacacaagaa aaatttacaa ttgattaaaa gtatccatgt 2104 cttggataca tacgtatcta tagagctggc atgtaattct tcctctataa agaataggta 2164 taggaaagac tgaataaaaa tggagggata tccccttgga tttcacttgc attgtgcaat 2224 aagcaaagaa gggttgataa aagttcttga tcaaaaagtt caaagaaacc agaattttag 2284 acagcaagct aaataaatat tgtaaaattg cactatatta ggttaagtat tatttaggta 2344 ttataatatg ctttgtaaat tttatattcc aaatattgct caatattttt catctattaa 2404 attaatttct agtgtaaata agtagcttct atatctgtct tagtctatta taattgtaag 2464 gagtaaaatt aaatgaatag tctgcaggta taaatttgaa caatgcatag atgatcgaaa 2524 attacggaaa atcatagggc agagaggtgt gaagattcat cattatgtga aatttggatc 2584 tttctcaaat ccttgctgaa atttaggatg gttctcactg tttttctgtg ctgatagtac 2644 cctttccaag gtgaccttca gggggattaa ccttcctagc tcaagcaatg agctaaaagg 2704 agccttatgc atgatcttcc cacatatcaa aataactaaa aggcactgag tttggcattt 2764 ttctgcctgc tctgctaaga cctttttttt ttttttactt tcattataac atattataca 2824 tgacattata caaaaatgat taaaatatat taaaacaaca tcaacaatcc aggatatttt 2884 tctataaaac tttttaaaaa taattgtatc tatatattca attttacatc ctttttcaaa 2944 ggctttgttt ttctaaaggc tttgttttcc tttttattat ttttttcttt tttatttttt 3004 tgagacagtc ttgctctgtc gctcaggctg gagtgcagtg gcacgatctc agctcactgc 3064 aacctcctcc tcccaggttc aagtgattct tgttcatcag cctcccgagt agctgggact 3124 acaggcatgt gccactatgc ccagctaatt tttgtacttt tagtagagac agggtttcac 3184 cacattggtc aggctggtct tgaaatgctg gcgtcaagtg atctgcctgc ctccgcctta 3244 cgtaatatat tttcttaatg gctgcataat atcacatcaa ataggcattt ttcaaacctc 3304 tttccttatt aaacatgtag actatatcca ttttttacta aaataaataa catttcagat 3364 aatatctttg cactgataat gttgccaagc catttctaaa gtgaccttat caatttaatt 3424 accattggat gagggtgttg ctttcatcgc accattgtag attgtctttt ttatttcaat 3484 ttgcgtttat ttataactgg ttgcaaaggt acacagaaca cacgctcctt caacttatct 3544 ttgataaacc caagcaagga tacaaaaagt tggacgacat tgagtagagt catggtatac 3604 ggtgctgacc ctacagtatc agtggaaaag ataaggaaaa tgtcactact cacctatgtt 3664 atgcaaaaca gttaggtgtg ctggggctgg atactgctct tttacttgag cattggttga 3724 ttaaagttta ggtaccatcc aggctggtct agagaagtct ttggagttaa ccatgctctt 3784 tttgttaaag aagagagtaa tgtgtttatc ctggctcata gtccgtcacc gaaaatagaa 3844 aatgccatcc ataggtaaaa tgctgaccta tagaaaaaaa tgaactctac ttttatagcc 3904 tagtaaaaat gctctacctg agtagttaaa agcaattcat gaagcctgaa gctaaagagc 3964 actctgatgg ttttggcata atagctgcat ttccagacct gacctttggc cccaaccaca 4024 agtgctccaa gccccaccag ctgaccaaag aaagcccaag ttctccttct gtccttccca 4084 caacctccct gctcccaaaa ctatgaaatt aatttgacca tattaacaca gctgactcct 4144 ccagtttact taaggtagaa agaatgagtt tacaacagat gaaaataagt gctttgggcg 4204 aactgtattc cttttaacag atccaaacta ttttacattt aaaaaaaaag ttaaactaaa 4264 cttctttact gctgatatgt ttcctgtatt ctagaaaaat ttttacactt tcacattatt 4324 tttgtacact ttccccatgt taagggatga tggcttttat aaatgtgtat tcattaaatg 4384 ttactttaaa aataaaaaaa aaaaaaaaaa aaaaaaaaaa aaaaa 4429 8 459 PRT Homo sapiens 8 Met Glu Lys Thr Cys Ile Asp Ala Leu Pro Leu Thr Met Asn Ser Ser 1 5 10 15 Glu Lys Gln Glu Thr Val Cys Ile Phe Gly Thr Gly Asp Phe Gly Arg 20 25 30 Ser Leu Gly Leu Lys Met Leu Gln Cys Gly Tyr Ser Val Val Phe Gly 35 40 45 Ser Arg Asn Pro Gln Lys Thr Thr Leu Leu Pro Ser Gly Ala Glu Val 50 55 60 Leu Ser Tyr Ser Glu Ala Ala Lys Lys Ser Gly Ile Ile Ile Ile Ala 65 70 75 80 Ile His Arg Glu His Tyr Asp Phe Leu Thr Glu Leu Thr Glu Val Leu 85 90 95 Asn Gly Lys Ile Leu Val Asp Ile Ser Asn Asn Leu Lys Ile Asn Gln 100 105 110 Tyr Pro Glu Ser Asn Ala Glu Tyr Leu Ala His Leu Val Pro Gly Ala 115 120 125 His Val Val Lys Ala Phe Asn Thr Ile Ser Ala Trp Ala Leu Gln Ser 130 135 140 Gly Ala Leu Asp Ala Ser Arg Gln Val Phe Val Cys Gly Asn Asp Ser 145 150 155 160 Lys Ala Lys Gln Arg Val Met Asp Ile Val Arg Asn Leu Gly Leu Thr 165 170 175 Pro Met Asp Gln Gly Ser Leu Met Ala Ala Lys Glu Ile Glu Lys Tyr 180 185 190 Pro Leu Gln Leu Phe Pro Met Trp Arg Phe Pro Phe Tyr Leu Ser Ala 195 200 205 Val Leu Cys Val Phe Leu Phe Phe Tyr Cys Val Ile Arg Asp Val Ile 210 215 220 Tyr Pro Tyr Val Tyr Glu Lys Lys Asp Asn Thr Phe Arg Met Ala Ile 225 230 235 240 Ser Ile Pro Asn Arg Ile Phe Pro Ile Thr Ala Leu Thr Leu Leu Ala 245 250 255 Leu Val Tyr Leu Pro Gly Val Ile Ala Ala Ile Leu Gln Leu Tyr Arg 260 265 270 Gly Thr Lys Tyr Arg Arg Phe Pro Asp Trp Leu Asp His Trp Met Leu 275 280 285 Cys Arg Lys Gln Leu Gly Leu Val Ala Leu Gly Phe Ala Phe Leu His 290 295 300 Val Leu Tyr Thr Leu Val Ile Pro Ile Arg Tyr Tyr Val Arg Trp Arg 305 310 315 320 Leu Gly Asn Leu Thr Val Thr Gln Ala Ile Leu Lys Lys Glu Asn Pro 325 330 335 Phe Ser Thr Ser Ser Ala Trp Leu Ser Asp Ser Tyr Val Ala Leu Gly 340 345 350 Ile Leu Gly Phe Phe Leu Phe Val Leu Leu Gly Ile Thr Ser Leu Pro 355 360 365 Ser Val Ser Asn Ala Val Asn Trp Arg Glu Phe Arg Phe Val Gln Ser 370 375 380 Lys Leu Gly Tyr Leu Thr Leu Ile Leu Cys Thr Ala His Thr Leu Val 385 390 395 400 Tyr Gly Gly Lys Arg Phe Leu Ser Pro Ser Asn Leu Arg Trp Tyr Leu 405 410 415 Pro Ala Ala Tyr Val Leu Gly Leu Ile Ile Pro Cys Thr Val Leu Val 420 425 430 Ile Lys Phe Val Leu Ile Met Pro Cys Val Asp Asn Thr Leu Thr Arg 435 440 445 Ile Arg Gln Gly Trp Glu Arg Asn Ser Lys His 450 455 9 322 DNA Homo sapiens 9 ggtcgacttt tcctttattc ctttgtcaga gatctgattc atccatatgc tagaaaccaa 60 cagagtgact tttacaaaat tcctatagag attgtgaata aaaccttacc tatagttgcc 120 attactttgc tctccctagt ataccttgca ggtcttctgg cagctgctta tcaactttat 180 tacggcacca agtataggag atttccacct tggttggaaa cctggttaca gtgtagaaaa 240 cagcttggat tactaagttg tttcttcgct atggtccatg ttgcctacag cctctgctta 300 ccgatgagaa ggtcagagag at 322 10 183 DNA Homo sapiens 10 tttgcagctt tgcagatacc cagactgagc tggaactgga atttgtcttc ctattgactc 60 tacttcttta aaagcggctg cccattacat tcctcagctg tccttgcagt taggtgtaca 120 tgtgactgag tgttggccag tgagatgaag tctcctcaaa ggaaggcagc atgtgtcctt 180 ttt 183 11 448 DNA Homo sapiens 11 aagaaggaga atccatttag cacctcctca gcctggctca gtgattcata tgtggctttg 60 ggaatacttg ggttttttct gtttgtactc ttgggaatca cttctttgcc atctgttagc 120 aatgcagtca actggagaga gttccgattt gtccagtcca aactgggtta tttgaccctg 180 atcttgtgta cagcccacac cctggtgtac ggtgggaaga gattcctcag cccttcaaat 240 ctcagatggt atcttcctgc agcctacgtg ttagggctta tcattccttg cactgtgctg 300 gtgatcaagt ttgtcctaat catgccatgt gtagacaaca cccttacaag gatccgccag 360 ggctgggaaa ggaactcaaa acactagaaa aagcattgaa tggaaaatca atatttaaaa 420 caaagttcaa tttagctgga aaaaaaaa 448 12 401 DNA Homo sapiens misc_feature 11,56,233,250,310,326,377,398 n=a, t, c, or g 12 ggccgcggca nccgctacga cctggtcaac ctggcagtca agcaggtctt ggccanacaa 60 gagccacctc tgggtgaagg aggaggtctg gcggatggag atctacctct ccctgggagt 120 gctggccctc ggcacgttgt ccctgctggc cgtgacctca ctgccgtcca ttgcaaactc 180 gctcaactgg agggagttca gcttcgttca gtcctcactg ggctttgtgg ccntcgtgct 240 gagcacactn cacacgctca cctacggctg gacccgcgcc ttcgaggaga gccgctacaa 300 gttctacctn cctcccacct tcacgntcac gctgctggtg ccctgcgttc gttcatcctg 360 ggccaaagcc ctgtttntac tgccttgcat tcagccgnag a 401 13 133 PRT Homo sapiens Xaa = Any amino acid 13 Ala Ala Ala Xaa Ala Thr Thr Trp Ser Thr Trp Gln Ser Ser Arg Ser 1 5 10 15 Trp Pro Xaa Lys Ser His Leu Trp Val Lys Glu Glu Val Trp Arg Met 20 25 30 Glu Ile Tyr Leu Ser Leu Gly Val Leu Ala Leu Gly Thr Leu Ser Leu 35 40 45 Leu Ala Val Thr Ser Leu Pro Ser Ile Ala Asn Ser Leu Asn Trp Arg 50 55 60 Glu Phe Ser Phe Val Gln Ser Ser Leu Gly Phe Val Ala Xaa Val Leu 65 70 75 80 Ser Thr Leu His Thr Leu Thr Tyr Gly Trp Thr Arg Ala Phe Glu Glu 85 90 95 Ser Arg Tyr Lys Phe Tyr Leu Pro Pro Thr Phe Thr Xaa Thr Leu Leu 100 105 110 Val Pro Cys Val Arg Ser Ser Trp Ala Lys Ala Leu Phe Xaa Leu Pro 115 120 125 Cys Ile Gln Pro Xaa 130 14 24 DNA Artificial Sequence primer 14 actttgttga tgaccaggat tgga 24 15 24 DNA Artificial Sequence primer 15 cagaacttca gcacacacag gaac 24 16 23 DNA Artificial Sequence primer 16 ttaggacaac ttgatcacca gca 23 17 24 DNA Artificial Sequence primer 17 tgtccagtcc aaactgggtt attt 24 18 23 DNA Artificial Sequence primer 18 agggagttca gcttcgttca gtc 23 19 24 DNA Artificial Sequence primer 19 ggtagaactt gtagcggctc tcct 24 20 24 DNA Artificial Sequence primer 20 gactgagctg gaactggaat ttgt 24 21 24 DNA Artificial Sequence primer 21 tttgaggaga cttcatctca ctgg 24 22 14 DNA Artificial Sequence primer 22 ttttgtacaa gctt 14 23 44 DNA Artificial Sequence adaptor 23 ctaatacgac tcactatagg gctcgagcgg ccgcccgggc aggt 44 24 10 DNA Artificial Sequence adaptor 24 ggcccgtcca 10 25 42 DNA Artificial Sequence adaptor 25 gtaatacgac tcactatagg gcagcgtggt cgcggccgag gt 42 26 8 DNA Artificial Sequence adaptor 26 cggctcca 8 27 22 DNA Artificial Sequence primer 27 ctaatacgac tcactatagg gc 22 28 22 DNA Artificial Sequence primer 28 tcgagcggcc gcccgggcag gt 22 29 20 DNA Artificial Sequence primer 29 agcgtggtcg cggccgaggt 20 30 15 PRT Homo sapiens 30 Tyr Gln Gln Val Gln Gln Asn Lys Glu Asp Ala Trp Ile Glu His 1 5 10 15 31 24 DNA Artificial Sequence primer 31 gactgagctg gaactggaat ttgt 24 32 24 DNA Artificial Sequence primer 32 tttgaggaga cttcatctca ctgg 24 33 22 DNA Artificial Sequence primer 33 acaagagcca cctctgggtg aa 22 34 23 DNA Artificial Sequence primer 34 agttgagcga gtttgcaatg gac 23 35 16 PRT Homo sapiens 35 Trp Lys Met Lys Pro Arg Arg Arg Asn Leu Glu Glu Asp Asp Tyr Leu 1 5 10 15 36 24 DNA Artificial Sequence primer 36 actttgttga tgaccaggat tgga 24 37 24 DNA Artificial Sequence primer 37 cagaacttca gcacacacag gaac 24 38 9 PRT Homo sapiens 38 Gly Leu Leu Ser Phe Phe Phe Ala Val 1 5 39 9 PRT Homo sapiens 39 Phe Leu Tyr Thr Leu Leu Arg Glu Val 1 5 40 9 PRT Homo sapiens 40 Leu Leu Leu Gly Thr Ile His Ala Leu 1 5 41 9 PRT Homo sapiens 41 Leu Ile Phe Lys Ser Ile Leu Phe Leu 1 5 42 9 PRT Homo sapiens 42 Met Leu Thr Arg Lys Gln Phe Gly Leu 1 5 43 9 PRT Homo sapiens 43 Phe Leu Tyr Ser Phe Val Arg Asp Val 1 5 44 9 PRT Homo sapiens 44 Ala Leu Leu Ile Ser Thr Phe His Val 1 5 45 9 PRT Homo sapiens 45 Leu Leu Ser Phe Phe Phe Ala Met Val 1 5 46 9 PRT Homo sapiens 46 Gly Leu Leu Ser Phe Phe Phe Ala Met 1 5 47 9 PRT Homo sapiens 47 Ser Leu Trp Asp Leu Arg His Leu Leu 1 5 

1. An assay for determining an expression level for a STEAP-2 (SEQ ID NO: 5) gene product, comprising: providing a test sample obtained from a subject having or suspected of having a cancer cell expressing the STEAP-2 gene product and a normal sample; determining the expression level of the STEAP-2 gene product in the test sample and the normal sample obtained from the subject; and comparing the expression level of the STEAP-2 gene product detected in the test sample and the normal sample obtained from the subject.
 2. The assay of claim 1, wherein the STEAP-2 gene product is selected from the group consisting of an mRNA that is at least 90% identical to an mRNA encoding SEQ ID NO: 5 or a protein that is at least 90% identical to SEQ ID NO:
 6. 3. The assay of claim 2, wherein the STEAP-2 gene product is the protein that is at least 90% identical to SEQ ID NO: 6 and expression is detected by contacting the test sample and the normal sample with an antibody or fragment thereof that specifically binds to STEAP-2 and quantifying the amount of the antibody bound to the protein.
 4. The assay of claim 3, wherein the antibody or fragment thereof is a monoclonal antibody.
 5. The assay of claim 2, wherein the STEAP-2 gene product is the mRNA that is at least 90% identical to SEQ ID NO: 5 and expression is detected by contacting the test sample and the normal sample with a polynucleotide probe that specifically hybridizes to the STEAP-2 gene product and quantifying the amount of the probe bound to the mRNA.
 6. The assay of claim 5, further comprising: (a) isolating mRNA from the test sample and the normal sample; (b) producing cDNA from the sample by reverse transcription using at least one primer; (c) amplifying STEAP-2 encoding cDNA so produced using STEAP-2 polynucleotides as sense and antisense primers; and (d) quantifying the amount of the amplified STEAP-2 cDNA.
 7. The assay of claim 6, wherein a polymerase chain reaction (PCR) is used to amplify the STEAP-2 encoding cDNA.
 8. The assay of claim 1, wherein the test sample and the normal sample are obtained from the subject.
 9. The assay of claim 1, wherein the test sample is obtained from the subject and the normal sample is obtained from a normal subject.
 10. The assay of claim 1, wherein the test sample is obtained from a prostate.
 11. An immunoassay for determining an expression level for STEAP-2 in a test sample, comprising: providing a test sample obtained from a subject having or suspected of having a cancer cell expressing the STEAP-2 gene product; contacting the test sample and the normal sample with an antibody or fragment thereof that binds specifically to STEAP-2 (SEQ ID NO: 6); quantifying an amount of STEAP-2 bound to said antibody or fragment thereof in the test sample and the normal sample obtained from the subject; and comparing the amount of STEAP-2 bound to said antibody or fragment thereof in the test sample and the normal sample, whereby expression levels of the STEAP-2 detected in the test sample and the normal sample obtained from the subject are assessed.
 12. The immunoassay of claim 11, wherein the antibody or fragment thereof is labeled with a detectable marker.
 13. The immunoassay of claim 11, wherein the antibody or fragment thereof is an Fab, F(ab′)₂, Fv or sFv fragment.
 14. The immunoassay of claim 11, wherein the antibody or fragment thereof is a human antibody, a humanized antibody or a chimeric antibody.
 15. The immunoassay of claim 11, wherein the test sample is obtained from a prostate.
 16. The immunoassay of claim 11, wherein the test sample and the normal sample are obtained from the subject.
 17. The immunoassay of claim 11, wherein the test sample is obtained from the subject and the normal sample is obtained from a normal subject.
 18. A kit for determining an expression level for a STEAP-2 (SEQ ID NO: 5) gene product, comprising: a STEAP-2 binding molecule, wherein the binding molecule binds specifically to the STEAP-2 gene product.
 19. The kit of claim 18, wherein the STEAP-2 binding molecule is an antibody or fragment thereof that binds specifically to the STEAP-2 gene product.
 20. The kit of claim 18, wherein the STEAP-2 binding molecule is a polynucleotide probe that specifically hybridizes to the STEAP-2 gene product. 